(KCEN) -- If you are getting ready to plan a trip out of town, listen up.
Hundreds of American Airlines flights were canceled last week and hundreds more were delayed after an increase in maintenance write-ups.
Nearly 400 flights were canceled according to flightstats.com, only 49 percent of American flights have been on time this month.
That's compared to 79 percent of flights arriving on time last year at this time.
The airline accuses it's pilots of increasingly calling in sick and filing excessive mechanical complaints.
However the pilots union says the problem is the airline's aging aircrafts.
Airline analysts say if these problems continue, the airline will also have to deal with a shift in their passenger loyalty.