Because they are paying exorbitant fuel costs driven by skyrocketing oil prices and chose to write down the value of their companies, Delta Air Lines and Northwest Airlines each took sizable first-quarter hits on earnings Wednesday.

Delta's loss leaped to $6.39 billion, equivalent to $16.15 per share, which was much worse than expectations. The average estimate of analysts surveyed by Thomson Financial was a 51 cents- per-share loss.

A year earlier, Delta lost $130 million. The airline didn't report a per-share loss because it was still in bankruptcy.

Northwest, which agreed last week to merge with Delta, reported a $4.14 billion loss that included a $3.9 billion charge to reflect the slumping value of its stock. Last year, the airline lost $292 million.

Delta's net loss came despite a robust gain in revenue. The carrier took in $4.76 billion in the quarter, up 12 percent from the first quarter last year. At Northwest, revenue totaled $3.13 billion, up 9 percent.

Delta's loss was driven by a $6.1 billion noncash charge to goodwill. Goodwill represents the value of a company's name that is on top of its assets.

When Delta emerged from bankruptcy a year ago, Delta valued its goodwill at $12 billion, based on an assumption that crude oil prices would not move much higher than $70 a barrel. Crude oil settled at $117.79 a barrel on Wednesday after touching $119.90 the day before.

The steady climb of oil has undermined Delta's stock market value. The share price is down 67 percent since the airline exited Chapter 11 bankruptcy last April 30.

Subtracting the goodwill charge, Delta lost $274 million in the first quarter, compared with a net loss of $6 million a year earlier. The increase was driven by a $585 million increase in fuel prices - Delta's largest cost.

The first quarter typically is the weakest three-month period for airlines, and taking a big goodwill charge-off now may have cleared the way for Delta to report better results in July.

"Based on guidance we've given for the second quarter, we expect to be modestly profitable," President Ed Bastian said.

Still, creditors may be wondering whether they bet wrong when they stuck with Delta instead of accepting a hostile $10 billion bid US Airways made for the airline last year. The Delta-Northwest union is valued at $3.1 billion.

The all-stock merger agreement announced April 14 by Delta and Northwest is meant to boost revenue and cut expenses, as well as fill in holes in each airline's international networks.

CEO Richard Anderson and Bastian flew to Salt Lake City last week to meet the airline's 3,500 local workers and assure them the Salt Lake City International Airport hub would not reduce operations nor close and move operations elsewhere.