[Gary Chester1]

How do I get movies to play on an iPad Pro from a USB stick?

[Rene Ritchie]

Sadly, you don't. Maybe Apple's contracts with iTunes force them to be hyper-vigilant about video piracy or maybe they simply don't want to burden normal people with the cruft of old-school computing, but USB sticks and file systems aren't something they've enabled on iPad.

Closest you can get is either dumping the files into Dropbox or iCloud and then loading them onto your iPad from there, or maybe doing something with cases that double as extended memory (never tried those so not sure how accessible they really are.)

[Jeroen7]

There are apps that support multiple video formats. But usually the files have to be on your iPad, or accessible from another pc/mac.
Storing the movies in those apps can be easily done via itunes on your computer. It's not as flexible as a usb stick but then you can play movies on your iPad.

[cuttheredwire]

HooToo + VLC Player

HooToo makes travel wifi routers that support a media center network share. You just need to plug your USB stick into the travel router, turn it on (be sure media sharing is enabled), and connect the the travel routers wifi network.

VLC Player can then use that share to play videos on the USB device. It should find it automatically. In fact, it can stream or download the videos on your flash drive.

Yes, this is not a "just works" case, but it works for me.

(Alternatively, you can use Readdle's Documents, which can put files on the flash drive, but connecting to HooToo is a bit tricky and it supports fewer media formats.)

So why HooToo? It's just a decent brand. I own one that replaced my wall charger and battery pack. Alternatively, I have a 32GB flash drive on my home router. Both routers have SMB/Samba shares and media shares built-in.

(All that aside, rumor has it that camera adapter SD or USB dongles can be used to transfer MP4 movies in, but not out. I also hear rumors that the new TV app has trouble with ripped media. It sounds like a gamble to me, but is worth looking into.)

Fun Fact: VLC can act as a wireless media device to stream and download movies from, while on the same network. I use this to put files on my older iPad from my newer iPhone which has more space. My phone often replaces my flash drive.

[pkcable]

Well they DO make lightning USB drives, but I have not used one and I don't know how well they work. As Rene said, iOS doesn't really have a file manager, so I'm not quite sure how these drives can work. Probably they have their own sort of file manager app. Results probably vary....

iPad & iPhone Flash Drives - Are They Worth It? | Everything USB