Yes, it is possible to get a First Class seat while on standby, but you are generally at the bottom of the priority list. Standby lists are typically cleared in a specific order: first, confirmed passengers who were bumped from earlier flights; second, elite status members looking for a "Same-Day Confirmed" change; and finally, "non-revenue" travelers (airline employees). If you are a standard passenger on a standby list for an earlier flight, the airline will first seat all passengers who have a confirmed First Class ticket. If seats remain, they will then process the Complimentary Upgrade list for their elite frequent flyers. Only after all elite upgrades have been processed will a standby passenger be assigned a First Class seat, and usually only if that is the only seat left on the plane. If you specifically want First Class, your best bet is to pay for a "Confirmed" change rather than relying on the "unassigned" standby process.