O - Observation Aircraft

Model	Designation	Manufacturer	Engine(s)	Crew	Other
OB-1		Boeing
O2B-1		Boeing	1 Liberty V-1650	2
OC-1	Falcon	Curtiss	1 Pratt & Whitney R-1340 Wasp	2	F8C-1
OC-2	Falcon	Curtiss	1 Pratt & Whitney R-1340 Wasp	2	F8C-3
XOC-3		Curtiss	1 Curtiss H-1640 Chieftain	2
O2C-1	Helldiver	Curtiss	1 Pratt & Whitney R-1340-4 Wasp	2	F8C-5
XO2C-2	Helldiver	Curtiss	1 Wright R-1820 Cyclone	2	XF8C-7
O2C-2	Helldiver	Curtiss	1 Wright R-1820 Cyclone or 1 Curtiss R-1510	2	XF8C-8, XF10C-1, XS3C-1
XO3C-1		Curtiss	1 Pratt & Whitney R-1340-18 Wasp	2	SOC-1 Seagull
OD-1		Douglas	1 Liberty
XO2D-1		Douglas	1 Pratt & Whitney R-1340	2
EO-1		Elias	1 Liberty	2
OE-1	Bird Dog	Cessna	1 Continental O-470-11	1	O-1B
OE-1A	Bird Dog	Cessna	1 Continental O-470-11	1	L-19A, O-1A
OE-2	Bird Dog	Cessna	1 Continental O-470-2	1	O-1C
OF-1	Mohawk	Grumman	2 Lycoming T53-L-3A	2	YAO-1
HO-1		Huff-Daland	1 Wright-Hispano E-2	2
XOJ-1		Berliner-Joyce	1 Pratt & Whitney R-985 Wasp Junior	2
OJ-2		Berliner-Joyce	1 Pratt & Whitney R-985 Wasp Junior	2
XOJ-3		Berliner-Joyce	1 Pratt & Whitney R-985 Wasp Junior	2
XOK-1		Keystone	1 Wright R-975 Whirlwind	2
OL-1		Loening	1 Packard 1A-1500	3
OL-2		Loening	1 Liberty V-1650	3
OL-3		Loening	1 Packard 2A-1500	3
OL-4		Loening	1 Liberty V-1650	3
OL-5		Loening	1 Packard 2A-1500	3	cancelled
OL-6		Loening	1 Packard 2A-1500	3
XOL-7		Loening	1 Packard 2A-1500	3
XOL-8		Loening	1 Pratt & Whitney R-1340 Wasp	3
OL-8		Loening	1 Pratt & Whitney R-1340 Wasp	2
OL-8A		Loening	1 Pratt & Whitney R-1340 Wasp	2
OL-9		Loening	1 Pratt & Whitney R-1340 Wasp	2
XO2L-1		Loening	1 Pratt & Whitney R-1340 Wasp	3
XO2L-2		Loening	1 Pratt & Whitney R-1340 Wasp	3
MO-1		Martin	1 Curtiss D-12	3
M2O-1		Martin	1 Curtiss D-12	3
NO-1		Naval Aircraft Factory	1 Curtiss D-12	3
NO-2		Naval Aircraft Factory	1 Curtiss D-12	3
XO2N-1		Naval Aircraft Factory	1 Pratt & Whitney R-1340-36 Wasp	2	XOSN-1
OO-1		Viking	1 Wright R-760 Whirlwind	4
XOP-1		Pitcairn	1 Wright R-760 Whirlwind	2
XOP-2		Pitcairn	1 Wright R-975 Whirlwind	2
UO-1		Vought	1 Lawrance J-1 or 1 Wright J-3 or 1 Wright J-5	2	UF-1
UO-1C		Vought	1 Lawrance J-1 or 1 Wright J-3 or 1 Wright J-5	2
UO-2		Vought	1 Aeromarine U-873 or 1 Wright-Hispano E-3	1/2
UO-3		Vought	1 Wright J-5	1	FU-1
UO-4		Vought	1 Wright J-5	2
UO-5		Vought	1 Wright J-5	2
O2U-1	Corsair	Vought	1 Pratt & Whitney R-1340-88 Wasp	2
O2U-2	Corsair	Vought	1 Pratt & Whitney R-1340 Wasp	2
O2U-3	Corsair	Vought	1 Pratt & Whitney R-1340 Wasp	2	O-28
O2U-4	Corsair	Vought	1 Pratt & Whitney R-1340 Wasp	2
O3U-1	Corsair	Vought	1 Pratt & Whitney R-1340 Wasp	2
O3U-2	Corsair	Vought	1 Pratt & Whitney R-1690 Hornet	2	SU-1
O3U-3	Corsair	Vought	1 Pratt & Whitney R-1340-12 Wasp	2
O3U-4	Corsair	Vought	1 Pratt & Whitney R-1690-42 Hornet	2	SU-2, SU-3
XO3U-5	Corsair	Vought	1 Pratt & Whitney R-1535 Twin Wasp Junior	2
XO3U-6	Corsair	Vought	1 Pratt & Whitney R-1340-12/18 Wasp	2
O3U-6	Corsair	Vought	1 Pratt & Whitney R-1340-12/18 Wasp	2
XO4U-1		Vought	1 Pratt & Whitney R-1340 Wasp	2
XO4U-2		Vought	1 Pratt & Whitney R-1340 Wasp	2
XO5U-1		Vought	1 Pratt & Whitney R-1340 Wasp	2
OY-1	Sentinel	Stinson	1 Lycoming O-435-1	2	L-5, L-5B
OY-2	Sentinel	Stinson	1 Lycoming O-435-1	2	XL-5F
XOZ-1		Pennsylvania Aircraft Syndicate	1 Warner Scarab or 1 Kinner B-5 or 1 Kinner R-5	2