{v. phr.}, {slang} To fly an airplane by feel and instinct rather than with the help of the instruments. * /Many pilots in World War I had to fly by the seat of their pants./
FLY BY THE SEAT OF ONE'S PANTS
Meaning of FLY BY THE SEAT OF ONE'S PANTS in English
Slang English vocab. Английский сленговый словарь. 2012