Flying around today, I think it was the least "diverse" I've ever seen AH. I saw maybe 5 planes in 2 hours that weren't a spit/nik/la7/p51. So, I figured I'd run the stats through for last tour and see what came up. I used to do this all the time, but I deleted all the old stuff I had, so I couldn't tell you if the trend towards consolidation is getting "worse" or "better". These are different from MiniD's stats, because I take all the planes with the exception of the level bombers and total the kills, then I just take every fighter (and attack plane) and work out the percentages.
total 511915
spits = 96,207 (18.79%)
spit5 + seafire = 44,333 (8.66%)
spit9 = 51,029 (9.97%)
N1K2 = 46,021 (9%)
La7 = 47,377 (9.25%)
P-51D = 41,139 (8.04%)
"Big 4" total = 230,744 (45.07%)
Others more than 10,000
109G10 = 17,618 (3.44%)
F4U-1C = 11,381 (2.22%)
F4U-1D = 16,952 (3.31%)
190D9 = 17584 (3.43%)
F6F = 19,920 (3.89%)
Hurri2c= 13,930 (2.72%)
Yak-9U = 10,821 (2.11%)
P-38L = 23,734 (4.64%)
Tiffie = 27,764 (5.42%)
Grand total = 58 planes
"Big 4": 45.07%
Suicide twins : 10.06% (55.13%)
next 7 : 21.12% (76.25%)
other 45 : 23.75%
USAAF total (A20,P38,P-51,P-47,P-40)
90,049 (17.59%)
Minus P-51D : 48,910 (9.55%)
USN total (F4F/FM2, F6F, F4U, TBM, SBD)
62,743 (12.26%)
RAF total (spit, hurri, tiff, temp, boston)
142,137 (27.76%)
IJN/IJA total (ki61, a6m, nik, d3a, b5n)
57,806 (11.29%)
minus nik: 11,785 (2.3%)
USSR total (la5,la7, yak, il2)
71,335 (13.93%)
minus la7 : 23,958 (4.68%)
LW total (190, 109, 110, ju87, 163, 262)
70,432 (13.76%)
kills scored by Hispano planes : 179,860 (35.13%)