Airline travel will nearly double over the next two decades, growing enough to add another airline every year, the Federal Aviation Administration predicted Thursday.

The number of passengers will grow from a projected 732 million this year to 1.2 billion in 2032, according to the FAA's annual forecast. Under another measure, the number of miles those passengers fly will grow from 815 billion last year to 1.57 trillion in 2032.

For comparison, that annual growth rate of 3.2% would add the equivalent of a JetBlue Airways every 10 months. JetBlue's passengers flew 2.5 billion miles in January.

"This year, more people will be flying more miles and we expect that to continue in future years," says Michael Huerta, acting FAA administrator.

The forecast released in conjunction with a two-day conference in Washington also projected growth of commercial operations at the largest 30 airports. Airports that are expected to grow the fastest, at more than 2.5% a year, are New York's John F. Kennedy, Washington's Dulles, Chicago's Midway, Orlando, Houston and Las Vegas.

Transportation Secretary Ray LaHood said the report underscored the importance of updating the country's air-traffic control system, under a project called NextGen.

"More and more Americans are relying on air travel and the Obama administration is committed to making sure the U.S. can meet our growing aviation demands," LaHood said.

Growth is expected despite expectations for higher fuel prices and a U.S. economy growing slower than some of the rest of the world. But FAA's pace of growth is slightly slower than last year's forecast, with a projection to reach 1 billion passengers three years later, in 2024.

The price of oil is projected to stay above US$100 a barrel this year and reach US$138 in two decades. Economic growth is projected at 2.6% each year domestically and 3.2% worldwide, according to FAA's projections by IHS Global Insight.