Photos: How UPS Next Day delivers

Because of the size of its air fleet--264 heavy jets, making it the 9th largest air carrier in the world--and the crucial importance of ensuring that packages get to their destinations on time, UPS maintains a contingency plan each night that involves having up to ten airplanes fueled and crewed and ready to step in to take another plane's place, for whatever reason. Those reasons could include such things as bad weather, maintenance issues, or crew problems. This is the "hot status" board, showing the status of the ten contingency planes, including each flight number, its airport of origin, and any notes.

This picture was taken as UPS operations managers were handling two separate cases where the contingency planes were likely to be needed, including a maintenance problem involving a Miami to Palm Beach, Fla., plane. On most nights a few of the planes might be needed, but sometimes none are.

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