Wiki has the wing loading for many of the ww2 planes, but not all. For example:
(from wikipedia)
P-51D Mustang
* Drag area: 3.80 ft² (0.35 m²)
* Aspect ratio: 5.83
Performance
* Maximum speed: 437 mph (703 km/h) at 25,000 ft (7,620 m)
* Cruise speed: 362 mph (580 km/h)
* Stall speed: 100 mph (160 km/h)
* Range: 1,650 mi (2,655 km) with external tanks
* Service ceiling 41,900 ft (12,770 m)
* Rate of climb: 3,200 ft/min (16.3 m/s)
* Wing loading: 39 lb/ft² (192 kg/m²)
* Power/mass: 0.18 hp/lb (300 W/kg)
* Lift-to-drag ratio: 14.6