sorry mate, the only station you can make bigger is the train station (max. is 7 by 7)
ship docks, bus stations and lorry stations are one square
and airports are small or big , no way getting around this
however, you can make any station 'bigger' by adding bus-lorry-train-ship' station, i don't know if you understand this
Trains, busses, lorrys and planes haven't changed 'YET'
They have changed the ships, just watch the latest patch
they are talking about busses, so i think that you just have to be patient a bit more