It's the Open GL test. Uncheck that and you will still get a comparable score. Open GL in SL will give close to half the Leopard score. It's not just an Air thing:
Leopard:
Results 131.32
System Info
Xbench Version 1.3
System Version 10.5.6 (9G55)
Physical RAM 2048 MB
Model MacBookAir2,1
Drive Type APPLE SSD SM128
CPU Test 114.46
GCD Loop 129.53 6.83 Mops/sec
Floating Point Basic 105.81 2.51 Gflop/sec
vecLib FFT 87.95 2.90 Gflop/sec
Floating Point Library 156.15 27.19 Mops/sec
Thread Test 217.93
Computation 351.82 7.13 Mops/sec, 4 threads
Lock Contention 157.86 6.79 Mlocks/sec, 4 threads
Memory Test 169.20
System 182.75
Allocate 190.35 699.01 Kalloc/sec
Fill 160.97 7826.50 MB/sec
Copy 202.02 4172.67 MB/sec
Stream 157.53
Copy 150.52 3108.91 MB/sec
Scale 147.64 3050.26 MB/sec
Add 167.34 3564.75 MB/sec
Triad 166.68 3565.64 MB/sec
Quartz Graphics Test 132.68
Line 130.74 8.70 Klines/sec [50% alpha]
Rectangle 151.99 45.38 Krects/sec [50% alpha]
Circle 115.05 9.38 Kcircles/sec [50% alpha]
Bezier 137.52 3.47 Kbeziers/sec [50% alpha]
Text 133.44 8.35 Kchars/sec
OpenGL Graphics Test 123.26
Spinning Squares 123.26 156.36 frames/sec
User Interface Test 158.57
Elements 158.57 727.75 refresh/sec
Disk Test 82.54
Sequential 64.72
Uncached Write 60.62 37.22 MB/sec [4K blocks]
Uncached Write 56.62 32.04 MB/sec [256K blocks]
Uncached Read 45.38 13.28 MB/sec [4K blocks]
Uncached Read 178.17 89.55 MB/sec [256K blocks]
Random 113.91
Uncached Write 51.03 5.40 MB/sec [4K blocks]
Uncached Write 79.16 25.34 MB/sec [256K blocks]
Uncached Read 1399.78 9.92 MB/sec [4K blocks]
Uncached Read 460.87 85.52 MB/sec [256K blocks]
Snow Leopard w. Open GL:
Results 118.20
System Info
Xbench Version 1.3
System Version 10.6 (10A432)
Physical RAM 2048 MB
Model MacBookAir2,1
Drive Type APPLE SSD SM128
CPU Test 131.60
GCD Loop 218.14 11.50 Mops/sec
Floating Point Basic 106.76 2.54 Gflop/sec
vecLib FFT 85.88 2.83 Gflop/sec
Floating Point Library 208.42 36.29 Mops/sec
Thread Test 246.38
Computation 338.87 6.86 Mops/sec, 4 threads
Lock Contention 193.55 8.33 Mlocks/sec, 4 threads
Memory Test 172.72
System 194.59
Allocate 230.20 845.39 Kalloc/sec
Fill 162.52 7902.08 MB/sec
Copy 203.24 4197.92 MB/sec
Stream 155.28
Copy 149.53 3088.52 MB/sec
Scale 146.47 3025.99 MB/sec
Add 163.86 3490.65 MB/sec
Triad 162.79 3482.56 MB/sec
Quartz Graphics Test 136.64
Line 122.43 8.15 Klines/sec [50% alpha]
Rectangle 148.86 44.44 Krects/sec [50% alpha]
Circle 128.00 10.43 Kcircles/sec [50% alpha]
Bezier 144.81 3.65 Kbeziers/sec [50% alpha]
Text 143.10 8.95 Kchars/sec
OpenGL Graphics Test 57.79
Spinning Squares 57.79 73.31 frames/sec
User Interface Test 185.35
Elements 185.35 850.64 refresh/sec
Disk Test 85.05
Sequential 67.20
Uncached Write 65.13 39.99 MB/sec [4K blocks]
Uncached Write 56.12 31.75 MB/sec [256K blocks]
Uncached Read 47.95 14.03 MB/sec [4K blocks]
Uncached Read 182.12 91.53 MB/sec [256K blocks]
Random 115.79
Uncached Write 51.74 5.48 MB/sec [4K blocks]
Uncached Write 80.87 25.89 MB/sec [256K blocks]
Uncached Read 1439.31 10.20 MB/sec [4K blocks]
Uncached Read 463.67 86.04 MB/sec [256K blocks]
Snow Leopard w.o. Open GL:
Results 141.30
System Info
Xbench Version 1.3
System Version 10.6 (10A432)
Physical RAM 2048 MB
Model MacBookAir2,1
Drive Type APPLE SSD SM128
CPU Test 131.83
GCD Loop 216.93 11.43 Mops/sec
Floating Point Basic 106.38 2.53 Gflop/sec
vecLib FFT 87.87 2.90 Gflop/sec
Floating Point Library 201.98 35.17 Mops/sec
Thread Test 236.73
Computation 267.21 5.41 Mops/sec, 4 threads
Lock Contention 212.49 9.14 Mlocks/sec, 4 threads
Memory Test 172.74
System 193.14
Allocate 224.69 825.15 Kalloc/sec
Fill 162.84 7917.43 MB/sec
Copy 202.38 4180.07 MB/sec
Stream 156.24
Copy 149.59 3089.73 MB/sec
Scale 146.59 3028.58 MB/sec
Add 164.37 3501.33 MB/sec
Triad 166.38 3559.27 MB/sec
Quartz Graphics Test 135.29
Line 120.87 8.05 Klines/sec [50% alpha]
Rectangle 148.19 44.24 Krects/sec [50% alpha]
Circle 127.15 10.36 Kcircles/sec [50% alpha]
Bezier 143.66 3.62 Kbeziers/sec [50% alpha]
Text 140.59 8.79 Kchars/sec
User Interface Test 186.95
Elements 186.95 858.01 refresh/sec
Disk Test 82.49
Sequential 64.14
Uncached Write 42.46 26.07 MB/sec [4K blocks]
Uncached Write 77.35 43.77 MB/sec [256K blocks]
Uncached Read 49.44 14.47 MB/sec [4K blocks]
Uncached Read 176.88 88.90 MB/sec [256K blocks]
Random 115.53
Uncached Write 51.80 5.48 MB/sec [4K blocks]
Uncached Write 80.06 25.63 MB/sec [256K blocks]
Uncached Read 1488.30 10.55 MB/sec [4K blocks]
Uncached Read 464.41 86.17 MB/sec [256K blocks]