Airplanes use a collection of airfoil components. Each airfoil component produces forces based on direction and speed of “airflow” around airfoil. In this case “airflow” is just a relative velocity of airfoil to a mass of air. Without any kind of wind it’s just a velocity of airfoil itself. Which means that you don’t need an engine to glide - spawn Fokker somewhere in the air and it should just fly on it’s own as it starts to fall and gain speed from that.
User input - steering is merely changing parameters of airfoil (ailerons) or just rotates airfoil (tail), then magic of air drag and lift happens and airplaine is pushed into a specific direction.
To assemble your own airplane you need to add airfoil component for each segment of your wing, the more segments you have, the more accurate behavior you should get. There is a minimal number of airfoil components you need to have on the wing - section of wing with aileron need to have a separate airfoil from the rest of segments. If you look at Fokker example, you can see that only top wing is made from more than two airfoils compared to lower wings, because lower wings (middle and bottom) don’t have ailerons.
There are no wing component so each airfoil need to know about size and aspect ratio of the full wing, you will see variables for that.
Propeller animation is linked directly to engine component as far as I remember, need to check code to say for sure.
You can completely ditch engine and just do AddForce on the root component, if force is large enough to accelerate vehicle it will eventually start to fly when velocity is large enough.
The hardest part is to make your airplane to fly in a stable way - this has more to do with airplane design than just some variables of the airfoils. I recommend using Scott Manley’s tutorials on aerodynamic in Kerbal Space Program:
principals are the same, the main difference in case of MMT would be that you can shift center of mass on the root component to get proper weight balance, instead of moving fuel tanks around as you would do in KSP.
To get going, start with something simple like a single airfoil wing - basically this would be a spoiler on the car. So add fuselage as a root component, with some adequate collision mesh - doesn’t have to be super precise but it shouldn’t be just a simple box either. Add single large airfoil for wing and one small airfoil for horizontal stabilizer - this is minimum that is necessary for airplane to be able to fly in a “straight line”. I don’t remember if I ever got anything useful out of a single wing without horizontal stabilizer.
Forgot about how you would control this without any control surface at the start - do like KSP does - add torque to your aircraft from button presses. Torque values in UE4 should be quite large - as UE4 uses cm as base unit conversion from metric to centimeter torque would be 10000.