Iran Air Force Day is observed in the Islamic Republic of Iran every February 8. This day commemorates the pledge of allegiance made by Iranian Air Force officers to Ayatollah Khomeini during the 1979 revolution. The Iranian Air Force, initially established as the Imperial Iranian Air Force in 1920 by Reza Shah Pahlavi, was renamed the Islamic Republic of Iran Air Force (IRIAF) following the revolution. The IRIAF faced significant challenges in its early years, including the loss of many leading officers and a U.S. embargo on weapon supplies, yet it played a crucial role during the early stages of the Iran-Iraq War. Iran Air Force Day serves as a professional holiday for all personnel serving in the IRIAF, which was estimated to consist of around 37,000 members in 2011.