why are plane tickets costing more lately

Airlines have used higher oil prices to justify fare increases of up to $60 per ticket since the start of the year. But the rising cost of fuel isn't the only reason why are plane tickets costing more lately.
The improving economy, a shrinking supply of seats and industry consolidation are also to blame.
"This is probably going to be the worst year we have seen in 10 years in terms of finding cheap tickets," says Tom Parsons of BestFares.com, a website for travel deals.
Airlines have the upper hand on prices for several reasons:
• The improving economy. Business travelers are expected to take 441 million trips this year, a 3 percent increase from 2010. As a result, airlines are reserving more seats for pricey last-minute bookings. That leaves fewer cheap fares for leisure travelers, who tend to book further in advance.
Fewer seats. During the recession, airlines reduced the number of routes and planes they fly. As travel demand picks up, this shrunken supply of seats allows the industry to charge more. Planes are 82 percent full on average, compared with 70 percent full before the recession hit in late 2007.
• Consolidation. Six airlines have combined into just three over the past 14 months — Delta and Northwest, Continental and United, Midwest and Frontier — leaving bargain-hunters with fewer choices.
American Airlines raised U.S. fares by $10 per round trip Wednesday but pulled back the increase Friday after other major airlines decided not to follow suit. It would have been the seventh broad price hike this year.
It isn't just the base fare getting more expensive. Checking bags, reserving an aisle seat and other services are no longer universally free.
Another change working against leisure travelers is the budding dispute between airlines and online travel sites. The airlines want to pay the sites lower commissions for each ticket purchased. The result for fliers: Not all available flights can be found on some sites. For instance, Orbitz, Expedia and Hotwire no longer list American Airlines flights.
Some high-traffic business and leisure routes, such as New York to Los Angeles, will see large hikes, Parsons says. The cheapest fare between those cities last July was $382. This year, it's $544. Parsons notes a handful of domestic routes, such as Dallas to San Francisco, are down thanks to new competition.

International routes aren't offering any relief, either. The cheapest plane tickets from Miami to Paris cost $1,250 this week, 53 percent higher than last year, according to SmarterTravel.
Vacationers looking for the cheapest tickets should aim to fly on Tuesday and Wednesday, the least busy days for the industry, Parsons says.
Booking hotel and air packages can also yield savings. Here's an extreme recent example found online: A trip to Las Vegas included two round-trip tickets on US Airways, three nights at the Excalibur hotel and two free show tickets, all for less than the cost of many round-trip fares to Las Vegas.