WASHINGTON — Federal safety officials urged Tuesday that aircraft owners be required to retrofit small planes with shoulder-lap seat belts, but stopped short of calling for the installation of air bags.

A three-year study of small plane accidents released by the National Transportation Safety Board found several cases in which air bags prevented serious injuries or fatalities. But investigators said that since only about 7,000 planes have air bags, there haven't been enough accidents yet to judge whether they should be required on all planes.

There are more than 200,000 general aviation aircraft, mostly small, single-engine planes, NTSB officials said. The average age of the planes is about 40-years-old, officials said.

A second study concluded that fatalities and serious injuries are 50 percent more likely to occur in accidents where pilots and passengers are wearing lap-only belts, rather than shoulder-lap belts. The study looked at 37,000 accidents involving single-engine planes between 1983 and 2008.

NEW YORK — Verizon Wireless made the long-awaited announcement Tuesday that it will start selling a version of the iPhone 4 on Feb. 10, giving U.S. iPhone buyers a choice of carriers for the first time.New Yorker Wes Moe can't wait. He has wanted one to accompany his iPad and Mac, but held back because he shares a Verizon plan with his wife, a BlackBerry user.“I'm super happy with all those other Apple devices, and I want that phone in my hands,” said Moe, 32.In the U.S., the iPhone has been exclusive to AT&T since it launched in 2007, frustrating many people who for one reason or another haven't wanted an AT&T phone.“I can't tell you the number of times I've been asked and my colleagues have been asked ... When will the iPhone work on the Verizon network?” said Apple's chief operating officer Tim Cook.Pre-orders for existing Verizon customers will start Feb. 3. The price will be $200 or $300 with a two-year contract, about the same as the iPhone through AT&T.