American Airlines quoted $496 for one passenger to fly from Miami to Charlotte, but just $155 per person when booking two passengers on the same flight. That means two tickets cost $310 total—$186 less than buying just one. Traveling alone more than tripled the per-person fare. That is one example from a new investigation into higher fares for solo travelers, and it raises an obvious question: why should traveling alone carry such a steep penalty?

American Airlines Wants $496 For One Ticket, But Just $310 For Two

Thrifty Traveler has published a revealing follow-up on airlines charging solo travelers more. His team examined 5,000 nonstop domestic one-way flights, sampling 1,000 each on American Airlines, United Airlines, Delta Air Lines, Alaska Airlines, and Southwest Airlines.

American charged solo passengers more on 33.5% of the flights sampled, compared with 10.6% on United.…