This 50,000 number must be from some Ebay listings.
LiTi technology exists, here is a 2-year old article quoting 6,000 cycles with 10,000 cycles on "some" models:
http://www.eetimes.com/author.asp?section_id=36&doc_id=1325358. Other sources report 3,000-7,000 cycles.
But then, Tesla Li batteries from Germany have 5,000 cycles while Chinese clones - only 1,000. Ebikes batteries work under different conditions than car batteries and have cycle life under 900, even those good ones. So, downgrade those 7,000-10,000 by factor of 5 or 10, and what do you get - 1,500 cycles maybe, if it works?
LiTi have lower energy density and lower voltage per cell, i.e. they are bigger/heavier.
BUT... sounds like they can fly, - no fire hazard.