Airline On Time Performance. Total time for multi-stop flights.
 

Interesting article in WSJ about peak scheduling.

http://online.wsj.com/articles/airli...hts-1410391905

Does the DOT track airline on-time performance for passenger’s where passenger’s itineraries are not non-stop flights?

On A->B->C, a delay in A->B may result in no delay at all if you can still get to B->C and it is on time. But it can result in a much worse delay if you miss your connection to B->C and the next available flight to C is many hours later or the next day.

Note that, in airline jargon, "direct" does not mean "non-stop". On some airlines, you may have a "direct" flight where you have to change planes and potentially miss your connection.

I think DOT only tracks on a by-flight basis ... the airlines aggregate as they deem most useful for marketing purposes

for a publication of WSJ's reputation, that article contains some pretty simplistic statements:
"Many passengers say they want the quickest trip possible."
"American tries to put planes with lots of connecting passengers at nearby gates to cut down on long walks ..."
"If bad weather hits at the wrong time, diverted flights and missed connections can cause widespread delays."
"Getting bags onto their next flight is a challenge with shorter connections."