The increase was a central component of the commission's decision to raise fares.
"They told us their strategy this year was going to be to raise fares," he said.
In part to pay for these higher costs, airlines attempted to raise fares.
Just three years ago, it raised fares about 10 percent.
The city council later refused to let the company raise fares above 7 cents.
"Airlines either need to raise fares, or the price of oil has to come down."
The railroad is determined not to raise fares, he said.
"There is more pressure on them now to raise fares."
United said it will not raise domestic fares for two years after completing the deal.
The increase was part of a policy to raise fares in moderate amounts every two years.