Expect higher prices and fuller flights -- but maybe a free ticket. By Anne Kates Smith, Executive Editor June 5, 2008 In recent weeks, delta and Northwest Airlines agreed to merge (although there are a lot of hurdles to clear before it's a done deal), Frontier Airlines filed for bankruptcy, and four smaller airlines -- Aloha, ATA, Eos and Skybus -- went out of business entirely.Meanwhile, a coming merger between United and US Airways is rumored, and British Airways is looking for alliances with American and Continental airlines. Unfortunately, as this struggling industry tries to right itself, passengers are facing fare increases, fuel surcharges and fees on top of fees for everything from legroom to luggage. Mergers won't help. Consider this: In six busy markets where Delta and Northwest now fly nonstop routes head-to-head, including Atlanta to Detroit and Minneapolis/St. Paul to Salt Lake City, the two carriers account for more than 85% of all nonstop passengers. Less competition in those markets will almost certainly lead to higher fares, says Kevin Mitchell, of the Business Travel Coalition. The good news is that your frequent-flier miles are safe. In fact, combining miles from two carriers may push some fliers over the 25,000-mile threshold for free tickets through most programs. The black cloud within this silver lining? Higher demand for reward seats when flights are likely to be scaled back is a recipe for frustration. In these turbulent times, travelers shouldn't buy tickets for travel more than three months in advance, advises travel blogger Tim Winship. And pay with a credit card so you can claim a refund -- just in case your airline disappears into the wild blue yonder.