A couple of years ago, American Airlines swapped out its pilots' "flight bag" for iPads loaded with the terminal charts and other reference materials they're required to carry. Losing the 35 lbs of materials for a tablet (some 8,000 of them) was a good tradeoff, but tonight an apparent glitch is grounding some of the airline's flights. American Airlines confirmed the issue in a statement to Engadget, saying "Some flights are experiencing an issue with a software application on pilot iPads", and that some of the flights had to return to the gate for a WiFi connection to fix the issue. According to the Dallas Morning News several dozen flights are affected, although it's not clear what caused the glitch.