I've been in a wheelchair for a short three weeks, but have had several flights and the have needed the assistance of several workers. I tip according to the amount of help I received. I had HORRIBLE service at IAH a couple of weeks ago. The first guy kept getting personal calls and left me in the middle of security while he chatted to his pal (they were making plans for after work so it was not a work call). He didn't get tipped much. I spent some time at the President's club and the plub staff called SEVEN times to get me a pusher - no one came so one of the staff took me part way down until she found two employees - chatting up each other and one took me to the gate - then dumped me by the gate (it was a delayed flight) in an area I could easily get hurt (my leg has to be straight out) so I moved myself. Needless to say she didn't get much either.

I had WONDEFUL service at LAX by 6 different people. I tipped no less than $6. Some had to take me a short ways; one took me all the way through immigration, helped with bags, etc. etc. etc. He got $20. I think tip dependant on what you feel it was worth. $5 may be too much in some cases - especially if it's in Houston!