To call William Poll a purveyor of delicacies is almost an insult. Sure, the grocery–cum–catering shop on Manhattan’s Upper East Side can sell you caviar and blini, as well as prepare you beef Wellington and pâté en croûte. They’ve been making those for almost a century, earning their place as something of a second kitchen for families in the neighborhood. But what they’ve really come to be known for among the comestible cognoscenti are the sort of Waspy dishes that withstand trends (and recessions): turkey-and-Swiss-cheese sandwiches, baked potato thins with watercress dip, chicken potpie, angel food cake, coq au vin, cole slaw, and black-and-white cookies.

Stop by the shop any Friday morning and, if you can make your way through the phalanx of double-parked S.U.V.’s and William Poll delivery trucks and not get trampled by the drivers scurrying in and out of the shop, you’ll see one of the city’s most curious pre-weekend rituals: those drivers are all fetching William Poll white-paper shopping bags, each bulging with tinned dishes, and each bearing what looks to be a six-digit secret code. In a way, they are: they’re the tail numbers for planes. The drivers are fetching food for private flights out of New York’s airports.