Recently, the Transportation Security Administration posted 28-day historical averages for security checkpoint wait times at every domestic airport, allowing travelers to tailor their itineraries to the times of less congestion. Visitors to the Web site, http://waittime.tsa.dhs.gov/index.html, must choose state, airport, day of the week, and time they plan to travel to get the historical average for the five-hour period bracketing their departure time.