As I am having my lunch I thought it might be fun to find out which airlines are OK to use on my next trip.
A search through the Air Travel forum using that exact phrase gave me this list of airlines to avoid:
Air New Zealand
Vieques Air Link
In addition, these are to be avoided in certain situations:
British Airways if you have luggage
Finnair if you're flying to China
Qantas to Hawaii
Ryanair if you have luggage
Southwest if you're a family
United if you're flying to Sao Paulo
Virgin Atlantic if you want extra legroom seats
I'm a little concerned about the inclusion of Air NZ (been happily flying them for a while now). I am relieved to see that Singapore is not there, but I did only get through the first 10 pages of results, and quite a lot of them were devoted to "Do not fly Spirit" (suspect that one is actually valid, from what I've read, I'd be avoiding them).