Yes, I do. You forgot that the round-trip ticket (which actually can not currently be had for under about $230) can also be as much as $3,153 for coach. This, incidentally, is more than 1/5 the cost of a new Chevy Cavalier (the ratio you mention in your example)...it's in fact about 1/3 the cost (for those keeping score, that's about a 60% increase).
Oh, by the way...in the mid-sixties, you got more food on board, had more flight attendants to attend to you, got free decks of cards and stationery, and were less likely to have someone sitting next to you in the smoke-filled cabin.
Oh, by the way...in the mid-sixties, the Chevy was much less well made than the 2004 Cavalier.
In any case, I'm not sure what your point is. Prices do not move in lockstep.
Some things become cheaper. Imagine, for instance, how much a 4GHz computer with 1GB RAM and 100GB of online DASD would have cost in 1965. I'll give you a hint...the best stuff that the DOD had at the time wouldn't come close to what you can get for a couple hundred bucks today.
On the other hand, some things become much more expensive. Nobody would have believed in 1965, for instance, that the cheapest houses in San Francisco would be over a half-million dollars by the end of the century...in the bad parts of town.
Such is the nature of an economy.