Is it possible to play Battlefield 2142 (Mac version) on the most current version of the Macbook Air? Ideally, I would prefer to play on osX, i.e., not through windows.
It should be possible. The main factor to consider would be the graphics performance, which, given that the Air has a Geforce 320M should be fine.
The tech specs for Battlefield 2142, according to Apple's downloads page are:
Mac OS X 10.4.9 or later
Intel Core Duo processor or higher
512MB of RAM (1GB recommended)
ATI X1600, NVIDIA GeForce 7300 GT, or higher video card (Intel GMA950 chipset not supported)
Minimum 2GB RAM,
Minimum 1.4GHz Core 2 Duo processor,
NVIDIA GeForce 320M graphics processor with 256MB of DDR3 SDRAM shared with main memory (meaning it'll deduct the VRAM is needs from your system RAM, which is 2GB minimum)
Should be OK!