I'm wearing hard contacts (-1.5 or thereabouts) and have been doing so for about 20 years. No problems when flying at all - even aeros.
Due to distortions at the edges of the frame I get a headache within 15 minutes if I switch to glasses so I have not worn those for a long time. In bed, with my lenses removed, I don't try to watch TV, but read a book instead (or watch the iPad).
On commercial airliners, or on hot days, I do get a bit irritation from the dry air. But that doesn't just mean my eyeballs are dehydrated - it means my whole body is dehydrated. So I use it as a sign to drink more, and that usually solves the problem. (It introduces another problem but that's not the subject of this thread.
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My medical specifies that I need to bring a spare set of spectacles too when flying. I have substituted this with a spare set of lenses when I'm flying aeros. Easier to carry in my pants pocket - the glasses case would be quite a hazard if dislodged from the pocket when flying aeros. And of course I typically don't have a problem with two lenses at the same time. So I can simply replace the one that gives a problem, while leaving the other in place. But to be honest, with only -1.5 I can still see pretty decent shapes in the distance and I can probably land the plane just fine if it's just one lens that's missing. (Note that carrying spare lenses instead of spare glasses may not be legal, depending on the interpretation of the regulations and the interpretation of the word "spectacles". But common sense in this case tells me that it's probably safer, in my particular situation, to carry spare contacts instead of spare glasses.)
Hard contacts do take a week or two to get used to if you've never worn them before. But in the long run they're relatively cheap and pretty easy to maintain.