I'd go with Migration Assistant since your older MacBook Pro won't have the drivers that are in the build of Lion that ships with the MacBook Airs. I've used that to migrate with my last several purchases.
When Apple finally ships the Thunderbolt Firewire 800 adapter, the process might be smoother, but it would work over Wi-Fi, or through an enclosure if you are able to take the HDD out of the MacBook Pro.