Okay, no Chinooks allowed.

(Yes, I know what a Chinook is in term of weather, but...)

Chinooks are the US Army's heavy lift helicopters. They are maintenance intensive, and prone to in flight issues. Given that a GOOD helicopter diesn't fly, but beats the air into submission, and defies natural law to do so, chinooks are NOT allowed in the bar.

A crew chief on one, when asked about the barrel of hydraulic fluid in the rear of the bird, pointed up to the mid-shaft synchronizing gearbox and said "See that? When is stops leaking, we stop flying. We give it a few pumps of fluid during flight to keep it leaking."