We cannot assure you either of a tradition that is particularly widespread in the USAF, or simply a sporadic event, a rite to exorcise the missions set for Christmas, but the 25 December an F-16 pilot of the 134 ° Fighter Squadron, "The Green Mountain Boys", was immortalized with a 'Santa Claus' hat while flying over Iraq and carrying the GBU-39 SDB (Small Diameter Bomb) to the bad boys of ISIS.
The photo was taken while the F-16 was refueled in flight by a KC-10 tanker Extender during a refueling mission in the skies of Iraq. The traditional 'Santa Claus' hat was worn over the flight helmet (probably an HGU-48 / P).
According to USAF sources, many pilots wear the traditional headgear when the 25 December mission.
(photo: USAF)