Update 9/24/2013: With the most recent update, Steam has fixed the issue that caused some players to crash if they did not disable the Steam In-Game Community.
A recent update to the Steam client has caused some Ace Patrol players to experience a crash when launching the game. The team is aware of this and investigating a fix now.
There is a workaround that will allow you to play the game in the meantime, if you're affected by this issue.
- In the Steam Library menu, right-click on Sid Meier’s Ace Patrol and select "Properties."
- Navigate to the "General" tab and make sure the "Steam Community In-Game" option is not checked. (See image below for reference.)
- Close the "Properties" menu and launch Ace Patrol.