— Keep looking for new seats. Even after checking in, seats can be changed at airport kiosks and on some airlines' mobile applications.
— Ask at check-in. Agents can sometimes put families in seats held just prior to departure for disabled passengers.
— Ask again. Gate agents and flight attendants can sometimes seek volunteers to swap seats.
— If flying Southwest Airlines set an alarm for exactly 24 hours before departure and check in online. The airline lets passengers pick their own seat at boarding. The earlier you check-in, the quicker you board the plane.
— If all else fails, offer nearby passengers candy or a drink to switch seats. Seriously, bartering works.
Scott Mayerowitz can be reached at http://twitter.com/GlobeTrotScott.