The apps are touch-and-go. Some are fairly reliable (assuming wherever you are you have decent data connection), others are abyssmal, and none of them seem to be consistent in either regard.

I have found, however, if you sign up for SMS updates through most airlines they appear to be quite reliable, and sometimes beat the in-airport departure boards by several minutes, particularly for gate changes.

Going to the airline's site and looking up the flight status has often resulted in a better update on delays, gate changes, and etc. for me than even the airport's status displays.

I think it's evolving. For me it definitely used to be that way. I am a semi frequent Delta flyer and in the last year or so their app has become so reliable and useful that the only reason I need the airport monitors is that it is often a second or two faster to just look up at a big display rather that going through the clicks and swipes to get to the data in my hand.

A big improvement has been wifi availability and stability on the plane. Not so much because I can browse the web in flight, but because regardless of whether I get in flight wifi, the airline's app uses it for free. So now that wifi is reliably always there, I know what's up and where I'm going before I walk off the plane.

Info viewed directly in the Apple Wallet screen is delayed, for sure. That applies to all apps - the tickets/"cards" don't seem to refresh that often. But what you see inside the app should generally be up to date, although I guess not all apps are equal.

The US airline's apps tend to be very good, sending you real time notifications of gate changes and flight delays. On Delta, the app even took me directly to a rebooking function when it notified me of a flight delay during a layover in ATL. Very good UX.

I get Tripit Pro through work and I find that I usually get push notifications through the app before the flight information displays in the airport (!) have updated. YMMV.

I had a great experience with Lufthansa recently. Wasn't using their app, but received very punctual emails with delay and gate information, to the extent that the gate change email came at pretty much the same time as the announcement. Had a new flight, ticket, and gate automatically within about 10 minutes of missing my connecting flight as well.

Alaska Airlines app works really well in my experience. Sometimes too well, as the gate agent starts the boarding process and suddenly a crowd forms at the gate before they have even announced anything.

I built and maintain one such service. Hopefully we don't have delayed gate information, but we DO ultimately rely on airlines, and we sometimes get very confusing information.

I don't fly too often, but when I do i've always found Google's flight info notifications to be quick and reliable.

The easyjet one is great, at least in CDG. Ryanair's is complete rubbish