United and Continental airlines plan to offer e-mail access on all domestic flights by the end of the year. For $16, passengers can plug their laptops into the Verizon Airfone on the seat back in front of them to check and send messages. No software download will be necessary, but attachments and big messages will cost extra, says Michael Pinckney of Tenzing Communications Inc., the small Seattle company that will provide the service. Tenzing's chief rival is Boeing, which is rolling out high-speed Internet service on Lufthansa, British Airways, Japan Airlines, and Scandinavian Airlines, priced at roughly $30. And Verizon Airfone president Bill Pallone reports that his company will offer wireless service in airline cabins as soon as the first quarter of 2004. With typically only one phone per row of seats, there may finally be a good reason to board the plane early.