Here is a link to the Wall Street Journal article about flight delays in the U.S. Flight Delays Newark Airport has been awarded the distinction of the airport with the most delays.
The Wall Street Journal also has a chart with the top-100 ranked flights in the U.S. in terms of delays. This chart provides flight numbers, frequency delayed and the average delay in minutes for each flight. Flight Delays
I plan to check this list and avoid these flights before booking. Planning to fly into or out of Newark? It seems morning departures and arrivals are best for now.