Argus
CIA man
Charley
airplane spotter
beagle
cloak-and-dagger operative
counterintelligence agent
counterspy
dick
double agent
espionage agent
eye
fire patrolman
fire warden
fireguard
flatfoot
forward observer
gumshoe
gumshoe man
hawkshaw
inside man
intelligence agent
lookout
lookout man
military-intelligence man
naval-intelligence man
night watchman
operative
patrol
patroller
patrolman
picket
private eye
reconnoiterer
roundsman
scout
secret agent
sentinel
sentry
skip tracer
sleuthhound
spy
spy-catcher
tec
undercover man
vedette
watch
watcher
watchkeeper
watchman
employee
security guard
airlines'
anti-submarine
ballyhoo
c-130
carrier-based
ground-attack
interferometer
low-flying
phototransistor
pilotless
rangefinder
single-engined
spelunking
tri-motored
trimotor
two-engine
ultralight
unpiloted
Potter
Trotter
blotter
cotter
dotter
hotter
imprimatur
mater
otter
plotter
potter
rotter
saltwater
squatter
totter
trotter
yachter