Originally Posted by rob_flies_ua

It's *possible*, especially if you are a) ontime (so this morning for example might sink your plans with SFO clouds) , b) near the front of the aircraft, c) no checked bags, d) have precheck, e) walk fast, f) already have a boarding pass for your VX flight, and g) have a backup plan in case you don't make it. Having said that, if any of those conditions are not true, I'd say there's a good chance you don't make it.