Directv apparently has pricing plans/contracts specific to aircraft - that's one of the reasons why the plan to shut down MPEG2 SD at the end of this year had to be pushed back. There were contracts for aircraft and oil rigs that went beyond that date that didn't permit them to shut down that service yet. The government may have some sort of special deal with Directv that covers a lot of ground. Stuff like government buildings in cities can easily get cable, but military bases aren't necessarily located where that's feasible (think remote airfields, missile silos etc.) so satellite would be pretty attractive for those markets.