We booked a flight on United to get us to Chicago to catch an Aer Lingus flight to Dublin and could not have been more disappointed. First the flight was delayed for an hour, then for three hours. We decided to approach Customer Service for help as we were in danger of missing our connection. After waiting in line an hour, we approached the agent who informed us we had been rebooked on an earlier flight. However no one had informed us of this in spite of the fact that they had both my cell # and email address; had we not stood in that line, we would have missed the earlier flight. Once boarded, we were forced to sit on the tarmac for an additional half hour. The captain explained we were waiting for the to load a wheelchair. I could have loaded multiple wheelchairs in that amount of time. Will avoid flying United in the future.