Probably one of the most compelling reasons for buying a leather flying jacket, and it hasn't been mentioned is that women love them. If your looking for a bird strike on the ground they always seem to go down well. There is some sort of top gun / pear harbour thing hard wired into women and it really does get them excited. If there is a stray bird there at a fly in your sure to be in there with the right flying jacket. Bring them up for a quick flip in the aeroplane, bit of negative g and float a packet of cigarettes off the coaming because they love that too. You have the rest of it all wrapped up - a touch and go or a full stop the choice is yours.
Other than that they are no use, mostly too short so you'd catch a chill in your lower back. If its function not form you're after then get some thermal underwear. Does more to keep you from foundering with the cold than either a flight jacket or a flying suit. Thermal underwear, even nato spec, has no known seduction properties unfortunately.
