There is no such thing as a family discount on U.S. airlines. Every child aged 2 or older requires a full paid seat — the same fare bucket as an adult. That reality hits hard when you have four kids.
Base Fares: Six Seats, Six Prices
On a typical domestic round trip, budget $150–$350 per person per leg in economy. A family of 6 (2 adults + 4 kids, all over 2) can easily spend $1,800–$4,200 in base fares alone before touching a single bag. One child under 2 who flies as a lap infant pays a nominal fee — roughly 10% of the adult fare on international routes, free domestically — but still occupies no purchased seat.
Seat Selection Fees
Basic economy fares on Delta, United, and American assign seats at check-in unless you pay to pick them. For a family of 6, guaranteed adjacent seating can cost $30–$60 per seat per leg — adding $360–$720 round trip just to sit together. Note: DOT rules effective 2024 require airlines to seat children under 13 adjacent to an accompanying adult at no charge on flights where such seats exist, but enforcement varies and basic-economy fare restrictions can still scatter families at booking time.
Checked Baggage
Each paid seat is entitled to the same baggage allowance as an adult. A lap infant traveling on a separate ticket (international) gets one checked bag and one carry-on in most programs. With 6 tickets you likely have 6 checked-bag allowances — but each bag on a fee-based carrier (Spirit, Frontier, Allegiant) still costs $35–$70 per direction. Budget $420–$840 in bag fees if you check one bag per person round trip.
Where to Find Real Savings
The highest-leverage tactic is a Southwest itinerary: no bag fees, no seat-selection fees, and Rapid Rewards points transfer to all six bookings. Flying Tuesday through Thursday shaves 15–25% off peak weekend fares. Booking 6–10 weeks ahead — not 4 months, when inventory is thin — tends to hit the sweet spot for domestic routes.
