The Federation is an advanced society whose origins in Human technologies means they may be inclined to solve problems the same way we have done so on Earth. Since their military options resemble most Human technologies and given the superior qualities of metamaterials such as tritanium used in the Federation, it does not seem unreasonable there are several ways to move and land such vehicles.
I am basing my answer on my military experience with modern U.S. aircraft carriers, there could be any number of answers you are not considering:
- They could simply have landing gear hidden strategically just like any other aircraft have always had. These fighters don't appear to be significantly larger than modern fighter aircraft so they can probably land the same way. I suspect they would prefer more modern facilities but could land on any relatively modern flight deck.
If they are part of a fighter squadron, given the nature of attenuated linear graviton beams or tractor beams and other field-pressor technology used in the Federation, when landing or taking off, they may simply be internally tractored to where they need to be in a fashion similar to the "arresting gear" use on-board aircraft carriers. The specially-calibrated tractor array pulls the ship to where it needs to be in the hanger. Humans need not even be involved, since the ship's AI is likely to be more sophisticated and more capable of the precision needed.
Another logical adaptation of pressor-field technology is to consider such vehicles have the capacity for Harrier-like movement. Rather than using their massive engines, they could simply utilize their antigravity and onboard thrusters to direct the ship where they want it. This could be a standard technology on most Federation fighters. Replace rotors with directed antigravity technology (which exists in the Federation deck plating everywhere) and they could be VTOL quite easily.
Summary: Since they look like air-superiority fighters, complete with wing surfaces, they appear to be able to land on planets with atmospheres so it would make sense they would have landing gear or VTOL capacities, such as the capacity to alter their wing configuration for landing in atmosphere or when tractor technology is not available.
Most blueprints and other such documents rarely show commonplace technology such as landing gear since they are "at rest" technologies which do not show the vehicle's fighting capacity. I can easily see most design schematics simply overlooking this vital technology in an effort to show what is deemed more important, their fighting, defensive and offensive capabilities.