I don't know what the mobile coverage is like where you were - But I have found here in the UK if I'm attending large events the it can be impossible to get a mobile signal.
I imagine this is due to large volumes of people calling each other to find out were they are.
Slashdot Mirror
the micro$oft flight sim series for control of other planes on and off the ground.
There are a few traffic jams now and then but mainly realistic.
google "declined the prize", millions seem to do it.
I don't know what the mobile coverage is like where you were - But I have found here in the UK if I'm attending large events the it can be impossible to get a mobile signal. I imagine this is due to large volumes of people calling each other to find out were they are.