Lindy Hop, having nothing to do with aviation,  Lindbergh, or hopping, is named after Charles Lindbergh's flight to Paris in 1927, when newspapers headlines read: "LINDY HOPS THE ATLANTIC".  The name Lindy Hop seems to have come from a joke or clever euphemism.  By the late 1920's a new, exciting style of dancing began emerging from Harlem.  This mostly black neighborhood in northern Manhattan (New York) was undergoing a cultural renaissance, producing incredible art, music, literature, poetry, and yes, dancing unlike anything ever seen before.  When "Shorty George" Snowden, the most popular dancer of his time, was asked by a reporter what he was doing, Shorty George replied that he was "doing Lindy's Hop."  Either Shorty was joking or thought that such a name might catch on given Lindbergh's popularity (or Shorty felt like he was flying and just thought of a clever metaphor - we don't really know for sure)  One way or the other, the name stuck.  This exciting style of dance that originated in Harlem Jazz Clubs would be forever known as Lindy Hop.  

Lindy Hop is the authentic American Swing dance.  The dance has no "hop" in it. On the contrary, it is smooth and solid, and while there is a constant rhythmic 8-count "pulse" that you feel in your bones, there is no hopping, bopping, or prancing in the dance.  It is an unabashedly joyful dance, with a solid, flowing style that closely reflects its music -- from the late 20's hot Jazz to the early 40's Big Bands. Just as Jazz combines European and African musical origins, Lindy Hop draws on African and European dance traditions. The embracing hold, and the turns from Europe, the breakaway and solid, earthy body posture from Africa. The dance evolved along with the new swing music, based on earlier dances such as the Charleston by the black population in Harlem.

from the American Institute of Vernacular Jazz Dance in Harlem...

Vernacular refers to indigenous dance forms created within a community and derived from native traditions, common social exchanges and a familiar culture.  Many ethnic groups contribute to the American melting pot, creating an incredibly diverse and broad range of vernacular dance in the United States. Examples include Native American ceremonial dances and Irish American clogging.  American Vernacular Jazz dance traces its origins to the customs of early African communities. These customs continue to evolve through social traditions danced primarily within African-American communities. Examples include Cakewalk, Charleston, Tap, Swing, Mambo, Blues, Break Dance, Salsa and Hip-Hop.  Occasionally, a social dancer emerges of such enormous talent as to transcend the original social environment and enter the performance and professional arenas.  Examples include Whitey’s Lindy Hoppers, Josephine Baker and Savion Glover. Yet whether the forum is professional or social, the Vernacular Jazz dance form finds its common denominator born of a community consciousness.

Until recent times, Jazz has been primarily dance music.  Infused with dancing rhythms, the music gradually evolved out of the clubs, ballrooms, picnics, and block parties that spawned it and into refined concert halls and high-class get-togethers.  Considering the rebellious, earthy, and unpretentious roots of the music, it is a shame that mainstream America sees Jazz as music only for the upper class or art geeks.  Imagine a day when Hip-Hop is seen in this way!   (as hip hop becomes less common in dance clubs around the country and more commonly choreographed for Broadway productions, we see history repeating itself).  

This is where the confusion comes.  When most folks think of "Jazz Dance", they think of the theatrical "Jazz Hands," Bob Fosse brand of dancing made popular by numerous Broadway and movie musicals.  While this dancing is a worthy art form in its own right - it is dancing as performance and has led to erasure in the American psyche of Jazz dance/music as social, earthy, funky, natural, sensual, and having communal groove. This self-consciously exaggerated, more stylized and less spontaneous style, uses the language of ballet and is ever evolving to the popular culture of Show Tune America.  It has grown into a blend of ballet (rooted in old Europe) and modern dance (rooted in Chinese Ballet).

While theatrical Jazz Dance draws from other theatrical cultures, vernacular or traditional jazz dance plants its roots in the theaters and ballrooms of black America , primarily before the 1950's.  Its roots are of Africa:  the grounded, earthy, and polyrhythmic expressions brought to America by the millions of people forced into slavery in the United States.     from Ken Burns Jazz...   

Music in general and jazz specifically both have strong links to the dance. One of the most influential elements of African culture was its polyrhythmic nature, which found expression in dance. Certainly, this is responsible for a great deal of what we think of as the vernacular American dance style in all of its myriad extensions. Long before the early 20th century, when jazz evolved, the various dance steps that had originated in and around the plantation set the modes of expression for whites who imitated the slave's moves, blithely unaware of the extent of parody in those dances.

Ragtime, with its dotted rhythms and new polyrhythmic syncopations made it possible for dancers to begin to evade the stress that had heretofore been placed on the downbeat. This eventually led to the even 4/4 swing of later dance styles, where dancers were free to stress whichever part of the musical phrase they desired. Dancing was the only social medium through which the men and women were allowed to touch, and the early 20th century saw a gradual breakdown of the various traditions that had kept them, up to that point, physically apart while dancing together. There was a direct link between the musical and dance styles, and what they represented in moral terms. Things came to a crisis in the early 1910s when the "animal" dances gained popularity. The first to catch on was the Turkey Trot, in which the dancers pumped their arms in imitation of the aroused fowl. Some of the other variants — the Bunny Hug, for example — let the participants wriggle and shake in a way that was quite daring for the time. Naturally, this led to indignation in the press and on the pulpit, which only made the dances more popular. 

The Charleston, composed by James P. Johnson, created a furor in 1923 and remains the dance most readily associated with the Jazz Age of the 1920s. Once again, it was the specific syncopation of the music — in this case anticipating the downbeats — that made the dance as visually provocative as the music itself. What separated Johnson from the great majority of his peers was his desire to combine not only ragtime and the European classics, but also to incorporate the "shout" dances he had witnessed as a child. At that time (and to some degree, to this day), virtually every African-American community, no matter its location, had a direct link to its Southern heritage. In his native New Jersey, Johnson heard native Virginians sing and dance in a way that made an indelible impression on him. The result was a rhythmic dynamism that later became known as "swing," and was the edifice on which Louis Armstrong built his radical transformations. It was also further proof to the public at large that so much of popular entertainment came directly from the Negro idioms.

The most innovative and influential jazz dance to emerge in the mid-20s was the Lindy Hop (named after Charles Lindbergh's famous Trans-Atlantic flight), created largely by George "Shorty" Snowden, a favorite at Harlem's Savoy Ballroom. The dancer and pioneer jazz critic Roger Pryor Dodge (who choreographed and danced in several collaborations with the Ellington trumpeter James "Bubber" Miley), wrote years later about what the Lindy Hop represented:

The Lindy Hop is the only dance which has both cross-rhythms and more than two time values. Besides the steps which are synchronized with the musical phrases in the Lindy, there are steps which cross the rhythm of the music in the same fashion as polyrhythms in music. Whereas many of the cross-rhythms possible in the Fox-Trot are due to the aimless meandering of the dancers, in the Lindy the presence of cross-rhythms was a matter of precise steps...

All in all Vernacular Jazz Dance, like club Hip-Hop dance, is social and done for the pure fun of it.  It "washes away the dust of everyday life."  It is a part of life rather than an activity that is separate from life, restricted to professionals, performers, and consumed passively by spectators. Vernacular dancing involves body, mind, spirit, feeling, and intensity. Most importantly it is very improvisational and personal in its expression.  It is not a performance.  It is just for having a good time.

From Ralph Eastman

The blues was never the province of solitary old men on back porches. In their way, critics who thought this have misunderstood the purpose and function of the music in much the same way as did the ante-bellum observers. While the blues may feature harsh and "mournful" sounding performances of downbeat lyrics, its totality is nonetheless a raucous, crude, ironic and rhythmic dance music. Listeners who insist that the blues are sad neglect the fact that the generic melancholy of typical blues lyrics is almost always juxtaposed with a sprightly, up-tempo instrumental accompaniment and performance style that belies the lyrical contents. The blues is the catalyst that brings temporary relief from a life of drudgery, not a catalog of those drudgeries.

from Downbeat class curriculum...

Hot, steamy, sensuous, and intimate as hell, blues dance soaks every seductive action from its African roots. Lacking wider social approval, it has developed and thrived in smoky jook joints and blues house parties. Never having been adopted by mainstream America, blues dance remains strongly entrenched in African principles of movement, not only in the motion of the hips, but also in the characteristic creation of dancing within a boundary. 

Contrary to some popular belief, Blues Dance is not automatically about sex.  It is automatically about emotion.  Intense Emotion.  It is very personal and intimate in ways that other improvisational dances like Lindy Hop cannot be simply because in blues there is so much less complexity in the music.  What is left is raw, unpolished, human vulnerability.  Blues dancing is an intimate expression or conversation between dancers that can be personal, spiritual, and emotional in ways that verbal communication fails.  When done correctly, Blues Dancing can be one of the most rewarding and indescribable experiences any level of dancer can have.