Here's the response I received. Hope it helps.

Well, when our cats were younger, we sedated them for
the long trip. At least, that is what the French vet
recommended. On the return trip, the Colorado vet
said that the would adjust faster if not sedated as
they had all of their instincts in working order. So
we did not sedate them and they did seem to adjust a
lot better on the last two trips (but maybe it is
because they got used to moving?)

Other stuff we did:
- call the airline 3 different times to be sure they
have everything in order (lables on cat kennels,
feeding instructions, water bottles, paperwork, etc.)

- carry with us 48 hours worth of food plus water to
give them as soon as we saw them off the plane

- put their travel kennel (open, with a favorite toy
or blanket) in the house 1 or 2 weeks before travel so
the box is not new for them (you have to take the toy
or the blanket out for the flight)

- make sure to have a couple of their "personal
effects" with you to put in the new house (location)
so when they do get there something smells familiar to
them

- ask the flight attendant as soon as you board if
they can check to be sure the animals made it in the
cargo (if appropriate - we always put them in the
cargo, so i don't have any experience with bringing
them on board the flight)

- we tried to have either a disposable litter box
(travel size) in our carry on or a new litter box
waiting at the new location

- try to forget about them during the flight!!

Here is a link to a .pdf doc that really helped me get
ready for our trip:
http://www.aphis.usda.gov/oa/pubs/petravel.pdf