Over the years, I've watched the travel times on certain routes increase steadily. You may also notice that morning flights have shorter travel times than afternoon flights on the same routes. (For example, search AA.com for flights between ORD and LGA. The first flight of the morning is scheduled at 1 hour, 58 minutes. As the morning progresses, flight times increase to 2h 5m, with a peak afternoon time of 2h 12m.)

At O'Hare, which is my local airport, it can take 20 minutes to taxi between certain gates and certain runways.