Boeing (BA) 737 Max 9 jets remain grounded after a panel blew off a plane mid flight, forcing United Airlines and Alaska Airlines to cancel hundreds of flights.

The financial impact on United and Alaska Airlines will be determined by the length of the grounding, according to Citi Managing Director and Equity Analyst Steve Trent.

“Roughly speaking, a 1% cut in available seat miles could result in a 2% to 2.5% reduction in pre-tax earnings,” Trent told Yahoo Finance Live. “On a short-term basis, it could be a big deal. But in terms of the findings so far, the worst-case scenario doesn't seem to be materializing at this point.”

Watch the video above to find out what Trent says is the one thing that could reveal if airlines are starting to lose faith in the big plane manufacturers.

For more expert insight and the latest market action, click here to watch this full episode of Yahoo Finance Live.

Editor's note: This article was written by Nicholas Jacobino

Video Transcript

- When passengers feel like there is a present issue that is either known or unknown? They feel a little bit more propensity to say, OK. What kind of aircraft am I flying on? Do I have the opportunity as was the case after the Max issues before back in 2018, 2019 where many of these airlines had to think about where are we going to allow for customers to change the aircraft that they were flying on? What type of pricing power do the airlines lose in that instance as well Here

STEVE TRENT: Yeah. I think probably it's still somewhat early to gauge the customer reaction. Absolutely passenger comfort is a very big deal. From what kind of aircraft are they flying on to people getting nervous about turbulence. You know, and as long as you're in a seat belt, turbulence is not really a dangerous thing but it's uncomfortable for many people.

So absolutely, this is something to watch for the group. If we do get into a situation where these problems are prolonged or there turns out to be another issue with the Max 9. I think from Friday's incident from everything we've seen, this was an extremely fortunate occurrence that it did not occur at cruising altitude when the air pressure differential is massively bigger and when people are moving up and down the cabin. That would have been an entirely different story.

So everything I can see, the flight crew did a marvelous job putting the plane into an emergency dive, getting back down to a safer altitude. Is that going to make a dent in people getting on the Max 9? I think it's a wait and see. But as I mentioned, you know, this seems to be, at this juncture, a manufacturing issue and not a design flaw.

- Steve, how do airlines, though, think about future orders, right? Just in terms of the competition out there between Boeing and Airbus. The fact that maybe United would think twice before making some of those future purchases down the line. Walk us through that type of thinking and some of the trends that maybe you are looking out for in terms of the impact that that could then have on these stocks.

STEVE TRENT: Yeah. So if one looks at the big airlines, especially, they all have skin in the game with one or both major manufacturers. So you really don't have great many options when one thinks about acquiring larger gauge planes. I think down the road, one of the things that it could be interesting to look at is to what extent do the airlines start to opt to lease instead of buy.

So if you do see a trend towards leasing, for example, it could mean, A, the OEMs continue to have a lot of production issues or B, there is some reticence on the airlines part to take on the asset risk of some of these new planes. So we haven't really seen that so far. You know, and fortunately, at least at this juncture, the loose bolts is somebody didn't put the door plug on properly, not like some kind of major flaw in the Max 9's fluid dynamics.