Definition of "Flags"

Suddenly the flag lieutenant grabbed an air vice-marshal's daughter by the hand and dragged her past the Charltons […] Flags was always doing something of this sort, and although Paul did not know him, he disliked it […]

1959, John Gilbert, Face in the Clouds, page 102

[…] up the Flag Lieutenant to inform him that a cow would have to accompany the distinguished passenger. "Flags" was rather horrified at this, so Louis, overworked and slightly irritable, said, "Very well — no damn cow, no damn general — […]

1971, Piet van der Byl, From Playgrounds to Battlefields, volume 1, page 193