Jim wrote:
Jet = F4
prop = Skyraider or O2
bomber = B52
whirlybird = HU2

It depends on what you were doing.

Bombing: USAF F-105 Thunderchief
Navy A-6 Intruder

FAC: O-1 Birddog
OV-10 Bronco

Close Air Support: F-100 (early days)
A-7D/E Corsair II
A-1D/E SANDY
A-4 SkyRaider

Surveillance: RB-66 Destroyer (USAF)
OV-1 Mohawk (Army)
A-3 Vigilante (Navy)

SAR: SH-3 Navy
HH-3 USAF

ECM: F-105 USAF (two seater)
EA-6 NAVY (four-seater)