Pretty harrowing first mission I'd say - a dozen Bostons attacking three different German-occupied airdromes in Holland at low level in broad daylight. It was a joint mission with the RAF. Read all about it here:
http://www.historynet.com/first-usaac-raf-joint-combat-mission-july-4th-1942.htmArtist Nixon Galloway commemorated the occasion with his work,
"First Mission" in 1991. It depicts the aircraft of Major Charles Kegelman, who flew so low he actually struck the ground with a wingtip and the bottom of the fuselage and lost a prop and engine in the process:
The bravery of these airman never ceases to amaze me.