I can only speculate, but the Belgian Army had been larger than that of the Dutch throughout the 20th century up to that point; also, the Dutch had a larger projected naval contribution as illustrated here:
Naval Forces (Force Goals December 1952) D-Day
Belgium: 1 DE, 2 AM, 3 AMC
Canada: 1 CVL, 4 DDE, 3 DE, 4 PC, 5 AMC, 12 MPA
Denmark: 5 DE, 2 PC, 3 AMC, 2 AMI, 2 SS, 8 MTB, 3 MPA
France: 1 CVL, 2 CA, 3 DDE, 16 DE, 11 PC, 6 AM, 15 AMC, 6 SS, 49 MPA
Italy: 2 CA, 3 DDE, 3 DE, 20 PC, 10 AMC, 8 MTB, 15 MPA
Netherlands: 2 DDE, 2 DE, 4 PC, 4 AM, 9 AMC, 2 AMI, 2 SS, 6 MPA
Norway: 1 DD, 1 DE, 3 PC, 2 AMC, 2 SS, 4 MTB, 4 MPA
Portugal: 4 DE, 2 AM, 3 MPA
UK: 2 CV, 3 CVL, 10 CA, 20 DD, 13 DDE, 29 DE, 19 AM, 17 AMC, 12 AMI, 31 SS, 12 MTB, 2 CM, 92 MPA
USA: 2 BB, 6 CV, 10 CVL, 10 CA, 145 DD, 21 DDE, 33 DE, 16 PC, 30 AM, 24 AMC, 60 SS, 153 MPA; 1 USMC Division + 1 USMC Air Wing + Amphibious Lift for one division
Additional Naval Forces D-Day + 180
Belgium: 2 AM, 4 AMC
Canada: 2 CA, 6 DDE, 21 DE, 21 PC, 9 AMC, 9 MPA
Denmark: 6 PC, 11 AMC, 7 AMI, 3 SS, 7 MTB,
France: 2 CA, 6 DDE, 21 DE, 10 PC, 3 AM, 5 AMC, 31 AMI, 4 SS, 11 MPA
Italy: 2 DDE, 2 DE, 10 PC, 7 AMC, 9 MTB, 7 MPA
Netherlands: 1 CVL, 2 CA, 3 DDE, 6 DE, 8 AM, 12 AMC, 14 AMI, 5 SS, 6 MPA
Norway: 4 DD, 1 DE, 2 PC, 2 AM, 5 AMC, 2 SS, 14 MTB
Portugal: 3 DE, 6 PC, 2 AM, 3 MPA
UK: 1 BB, 1 CVL, 4 CA, 29 DD, 15 DDE, 63 DE, 33 PC, 38 AM, 129 AMC, 40 AMI, 2 SS, 6 MTB, 1 CM
USA: 1 BB, 6 CV, 1 CVL, 5 CA, 63 DD, 77 DE, 15 PC, 40 AM, 16 AMC, 10 SS, 90 MPA; 1 USMC Division + 1 USMC Air Wing + Amphibious Lift for one division
Edit: Here are the air numbers, for what its worth:
Frontline Aircraft Goals 1952
Belgium: 409 (144 Fighter/Interceptors, 225 Fighter-Bombers, 24 AW Fighters, 16 Transports)
Canada: 96 (96 Fighter/Interceptors)
Denmark: 131 (96 Fighter/Ground Attack, 16 Fighter-Interceptor, 16 AW Fighters, 3 Tac Recon)
France: 478
Italy: 300 (125 Fighter/Interceptor, 175 Fighter-Bombers,
Netherlands: 207 (80 Fighter/Interceptor, 75 Fighter-Bombers, 24 AW Fighters, 12 Tac Recon, 16 Transports)
Norway: 135 (113 Fighter/Ground Attack, 6 Tac Recon, 10 Transports, 6 Maritime)
Portugal: 100 (100 Fighter/Ground Attack)
UK: 1516 (604 Fighter/Interceptors, 228 Fighter-Bombers, 274 AW Fighters, 160 Medium Bombers, 60 Light Bombers, 72 Tac Recon, 58 Transports)
USA: 695 (435 Fighter-Bombers, 64 Light Bombers, 100 Tac Recon, 96 Transports)
Total: 4067
1953
Belgium: 491 (192 FI, 225 FB, 40 AWF, 18 Recce, 16 Transport)
Canada: 225 (225 FI)
Denmark: 199 (175 FGA, 24 AWF)
France: 1218 (480 FI, 450 FB, 72 AWF, 96 LB, 72 Recce, 48 Transport)
Italy: 579 (200 FI, 225 FB, 36 AWF, 16 LB, 54 Recce, 48 Transport)
Netherlands 260 (96 FI, 100 FB, 36 AWF, 12 Recce, 16 Transport)
Norway: 194 (150 FGA, 25 AWF, 9 Recce, 10 Transport)
Portugal: 175 (175 FGA)
UK: 1960 (776 FI, 192 FB, 348 AWF, 370 LB, 144 MB, 80 Recce, 50 Transport)
USA: 1125 (300 FI, 500 FB, 25 AWF, 96 LB, 108 Recce, 96 Transport)
West Germany: 579 (150 FI, 375 FB, 54 Recce)
Total: 7005
1954
Belgium: 531 (192 FI, 225 FB, 64 AWF, 18 Recce, 32 Transport)
Canada: 300 (300 FI)
Denmark: 239 (175 FGA, 48 AWF, 16 Transport)
France: 2018 (960 FI, 600 FB, 110 AWF, 192 LB, 108 Recce, 48 Transport)
Italy: 852 (375 FI, 225 FB, 84 AWF, 48 LB, 72 Recce, 48 Transport)
Netherlands 374 (144 FI, 150 FB, 36 AWF, 16 Recce, 16 Transport)
Norway: 226 (150 FGA, 50 AWF, 16 Recce, 10 Transport)
Portugal: 200 (200 FGA)
UK: 2552 (930 FI, 352 FB, 408 AWF, 580 LB, 152 MB, 80 Recce, 50 Transport)
USA: 1515 (450 FI, 600 FB, 60 AWF, 96 LB, 90 MB, 108 Recce, 96 Transport)
West Germany: 1158 (300 FI, 750 FB, 108 Recce)
(I'd note that the American numbers are lowballed based on what was forward deployed to Western Europe, with a lot of extra tacair reinforcements from CONUS not detailed in the document)