United airline delayed flight 877-297-0699 Nothing tests your patience like sitting at the gate watching the clock. My last united airline delayed flight was a three-hour wait in Chicago. Instead of joining the massive line at the help desk, I tried calling 877-297-0699. It was a game-changer! While everyone else was frustrated, the agent on the phone helped me look at other connections. If your flight is lagging, the best way to modify your travel plans is to get someone on the line who can see the full flight map immediately.