Lafayette Escadrille was a French unit and flew French aircraft, not the British SE 5. Also It had been disbanded a few months before April 1918 when the Red Baron was shot down.
The actors playing French characters (Monique, her father, her 2 brothers) are all speaking with bizarre and non French sounding accents, particularly Monique.
When Mr. Crane meets Mr. Rourke in his office, Rourke instead says, "Mr. Phillips, please sit down."
Phillips is the surname of Helen, the woman Crane intends to marry.