Without development I would probably value this at around mid $xx
Although they are nice enough keywords with plenty of potential, I just can't see them selling easily for a decent amount unless you can find a very motivated end user.
On the other hand, developed, they could do quite well. A little bit of work and could probably fetch low to mid $xxx as a developed site.
For the flight/airfare site, you probably could make an affiliate or white label type site and then concentrate on building traffic to it. The car loan one could make a nice car loan comparison type domain.