At the airport ask how much it costs to upgrade your ticket

If you’re not a bigwig or a coveted member of an airline’s frequent-flier program, it’s unlikely that you’ll score a free first-class upgrade without precedent (i.e., being bumped from a flight). Many airlines will, however, let you buy first-class upgrades—if available—when you check in at the airport, particularly if they fear a flight will be oversold. You might get lucky and end up paying only $100–$200 more for first. On longer flights the extra cost could well be worth it. Before you head to the airport, check to see what a first-class seat on your flight is going for to ensure that you are getting a good deal.