In theory, gate agents with these devices can anticipate the need to rebook a flight after a missed connection, instead of waiting for passengers to ask. In the future, new technology may allow airlines to know if travelers are stuck in traffic on their way to the airport, thanks to GPS-enabled smartphones, or offer an earlier flight if a traveler shows up with time to spare.

Image Ken Ihrig, a crew chief for American Airlines, manages luggage loading with a hand-held device. Credit... Brandon Thibodeaux for The New York Times

Passengers traveling this summer will see only a glimpse of the new technology, though it will be introduced at airports over the next year or two. For now, the airlines remain dependent on computer systems first built a half century ago that have been layered with updates upon updates  “a spaghetti of networks,” as one analyst described it  that do not always communicate well with one another, or with passengers.

So some airport screens may say a flight is on time, while the gate information shows it has been moved to another terminal and the airline employees standing behind their monitors say the flight has, in fact, been delayed two hours.

And the experiences of passengers are more like Dr. Joan Bengtson’s. Dr. Bengtson, a gynecologist who lives in Boston, said that she was once stranded because of a snowstorm, and it took two days for the airline to rebook her. Meanwhile the phone number she was given remained busy for hours.