An United Airlines Boeing 737 is parked out front of the new Boeing 737 Delivery Center on October 19, 2015 in Seattle, Washington. 
An United Airlines Boeing 737 is parked out front of the new Boeing 737 Delivery Center on October 19, 2015 in Seattle, Washington.  - 

Since the mega-merger between United and Continental Airlines five years ago, United has had some turbulence: It scores among the lowest of any major airline in most major categories, former CEO Jeff Smisek is under federal investigation for allegedly trading favors with the New Jersey Port Authority and though replacement Oscar Munoz has been trying hard to clean up United's act, he's had serious health issues, including a very recent heart transplant.

Drake Bennett is a staff writer for Bloomberg Businessweek who wrote about United's struggle for a comeback:

If you look at the numbers, the kind of performance metrics that airlines are measured by, things like on time arrival, cancellations, mishandled bags, bumped passengers, United has reliably performed worse among all non-discount airlines. They've also made customers less happy than any other major airline, and then you have these particularly vivid anecdotes that for a lot people seem to symbolize the 'United Experience.' Things like, a disabled man who had to crawl off a plane because there wasn't an aisle wheelchair to take him to the jetway, or a little girl whose parents couldn't find her because no one had met her at her flight when it arrived in O'Hare, and she was traveling as an unaccompanied minor.

You hear a lot of stories like this, and you also hear a lot of stories just about how people feel like they're unable to get through to anyone at United to tell them about their problems or to fix things that there's really just this sense employees of the airline don't really have a lot of agency to help out customers. And so customers have really turned on the airline, especially in the first couple years, they lost a lot of very lucrative business travelers, which really is the lifeblood for these non-discount airlines.

Read more from Bennett's story at Bloomberg Businessweek

Follow Molly Wood at @mollywood