5,000 tickets a day only were offered for the public. People who couldn't buy tickets were lined up on the road and around outside the Airshow location to watch the air displays.
A lot of people where already camped near the Sakhir area as it's the camping season in Bahrain this time of year, so they watched the airshows for free
.
Here's a video describing the evolution of the Airshow idea and how it's meant to be a bit different.
Bahrain International Airshow - Preview 2010