I have had a mixed bag of success with my phone coming back from Airplane mode. Sometimes it locks in before I even get back to the telephone screen, other times it takes a few minutes. I think it is hard to really compare to other devices sitting next to you because of how the innards work on each.

What happens if you switch it to airplane mode while just sitting at your desk and then switching it back, does it work better then? It could be an interference thing too I suppose with the airport and all the equipment.