I was a air/eam driver for a while and it really comes down to your personal situation! This particular situation you shouldn't have answered the phone because you had something to do but if you want hours and need the money then going out of your way, i.e... coming back to run air usually gives you a better chance of them using you again to run air, sometimes if you have a lot of area knowledge they will use you for additional work other then delivering air.
Some supervisors hold grudges and will stop using you if your not consistent, that depends on how desperate they are. If you suck and have a lot of late air it won't matter anyways but it really all depends on what you want.