Fly below the 0 C level, if safe to do so.
But at the same time, you fly below the radar.
The training area was well known to American forces, and aircraft were not supposed to fly below 10,000 feet when over it.
The die must fly about a foot below the ceiling.
It's a million to one that they were flying below radar level.
The authors are great ones for flying below the radar.
The supposed bomb was thought to be triggered by flying below 5,000 feet.
The airline's planes have been flying only about 55 percent full for much of this month, below the level necessary to break even.
Until recently, the crimes flew below the radar of Federal officials.
Let them try to fly below tree level, though.