You won't know unless you ask, and that can also apply to scoring an upgrade. Some seasoned travelers have gotten upgraded during check-in at the airport or at their gate. There's no easy way to do this and no guarantee it'll work.

Yes, you can almost always upgrade your seat at check-in, provided there is availability in the higher cabin. In 2026, most airlines have automated this process through their mobile apps and kiosks. When you begin the check-in process (usually 24 hours before departure), the system will often present "last-minute" upgrade offers to Premium Economy, Business, or First Class at a significantly lower rate than the original fare difference. On carriers like Southwest, which transitioned to assigned seating in 2026, you can upgrade to "Extra Legroom" seats during the check-in window. If the app doesn't show an offer, you can ask a gate agent once you arrive at the airport. Note that "operational upgrades" (free moves due to an overbooked economy cabin) are rare and prioritized for elite loyalty members; most check-in upgrades will require payment in cash or miles. However, checking in exactly 24 hours prior is the best way to snag these discounted seats before other passengers take them.