In short, United reported $107 million of it's loss because passengers earned miles for flying. I estimate you'll be seeing statements like this one until United can figure out how to utilize the new accounting method for a profit:
"If the company had continued to account for Mileage Plus under the old incremental cost method, first quarter passenger revenue is estimated to have been $107 million higher."
For more of the non-accountant view on this, check out: "How does Fresh Start Accounting effect Mileage Plus".
For the complete filing, go to united.com.