My dad was late to the Dallas/Fort Worth International Airport due to a terrible accident on Highway 121. He arrived at the counter 30 minutes before his American Airlines flight to Tokyo was to depart. He tried to self-check but the system forced him to talk to a person at the counter.
He was told he needed to reschedule to a later flight from Dallas to Japan. The American agent told him there would be a $250 rescheduling fee. That was understandable because it was a non-refundable ticket. Then they tacked on a $1,000 fare difference, so the additional $1,250 (plus tax) ended up costing about 150% of the original ticket. Even the American ticket counter agent was stunned.
There were additional empty seats on that flight. I'm sure there were quite a number of people who missed their flights due to the accident right outside the airport. I have tried to contact American through its online system, e-mail, Twitter and Facebook to no avail.