jis, bear with me as I'm not too interested in tech stuff, but what is IFE ? Is internet on board a flight usually an extra cost or available to everyone within the ticket price. When we travel I use a small laptop, more or less just use the phone as a phone.
Depends on the airline and/or the aircraft. I remember way back in the 90s, I flew first class once and while the movies only looped, we all had personal displays and could select from several channels. The traditional method was to have just regular TVs and one watches the movie from just a few in the cabin.
By about 2007, personal seat back displays were more common although they were generally just looping the same content rather than any kind of on demand content. I flew on one of the newer 777s back then, but on an older 747 going back home. The older plane still had CRTs. Maybe one at each bulkhead and several that dropped down from the ceiling.
I guess the latest is inflight movies on demand. They can be through a seatback display although a lot of shorter range aircraft don't have them. Inflight Wi-Fi can be used to stream content to passengers. It doesn't necessarily need internet access because the systems have all the content already stored on a server on the plane. Satellite internet may be available, although how it's paid for varies. There might be a charge per 4 hours, and entire flight, or even a monthly rate for frequent travelers. I think some are even a network across different airlines.
The content might require installation of an app on certain devices - like gogo Inflight. A few airlines build their entertainment systems into their general purpose airline apps. But many will just bring up the sign-in/payment information when one tries to pull up any web page. I've rarely paid for it since it can be pricey (and unreliable) but often they might have direct access for free to specific websites - especially the airline.
In kind of unrelated stuff, I do remember the time we needed to get visas after booking overseas travel, but forgot to print out an itinerary or ticket receipt. The consulate referred us to a computer service place, but it was closed. We asked at a hotel and they said they had paid internet access (using a credit card) at a computer in the corridor. But we checked and they strangely had a free "boarding pass" printing option with free access to several airline websites (including our airline). We could pull up our reservation that way and the printing was free. I'm not sure if it was meant for non-guests to use for free, but an employee sent us there so I didn't feel bad about it.