It would be very cool if you could add actual tank guns. Turrets and chassis are available to everyone right now, since they can be built using fuselage blocks, rotors, wheels and so on. We're only missing tank tracks and wheels, but that' another story. They would have a few customizable parameters:
1. Caliber (in mm or inches)
2. Length (in calibers, like L/55 which means 55 times the caliber)
3. Smoothbore (worse accuracy, higher dmg) or rifled (higher pen, better accuracy, lower dmg)
4. Standard shell: APHE, APCR, HE, HEAT, APDS or HESH
5. Muzzle brake or fume extractor
6. Autoloader (loads automatically), drum-fed (single-shot cannon that fires from a drum), autocannon (fires a salvo of rounds automatically) or single-shot.

Regarding point 6, I recommend you check out the following tanks for clearing it up: T-14 Armata, AMX 13 90 or AMX 50 100, M5 Stuart and Tiger I (or Tiger II, aka "Königstiger")

It would be nice if gunner A.I. would be added to the game considering that bombers really don't have a way of defending them selves from enemy aircraft. The only current way of "defending" bombers is to use rotors and put guns on them to allow the gun to have free movement. Sure the gun has free movement but its really tedious and difficult to actually manage to kill and enemy aircraft on your tail with out shooting your own tail off or getting shot down before you even get a lead or shot on him. I guess the only way to portray this new A.I. if it will ever be addded is to make a gun turret part but thats for another suggestion.

SimplePlanes is a simulation game, which is great because you can build whatever you want and then expect it to fly exactly like it would in real life!

Not exactly...

One massive thing is stopping any aircraft's flight dynamics dead in its tracks: drag.

SimplePlanes drag model in its current state is so bad in fact, that I recently had to cut my aircraft's drag by almost 98% and that only got it close to flying properly. Engines need to be more powerful to make adequate thrust (which really messes with takeoff performance) and when you send your power to idle at 10,000 feet it feels like you just ran into a wall with how fast your plane decelerates, and you need to enter a vertical nosedive to gain speed again.

THIS IS NOT REALISTIC!!!

This is why the drag model needs a total overhaul. Airplanes simply need to make less drag than they currently do in SimplePlanes. As in, 98% less drag. This will allow for some awesome stuff like better gliders and more efficient engines, as well as much better thrust physics.

Also, instead of focusing on individual parts, I suggest that the drag model looks at the plane as a whole and figures out how much air resistance the entire shape will create. Do away with the drag points system and instead use a Drag Coefficient to determine how much drag your airplane will create.

Implementing both of these things would help the flying part of the game a lot, and would help builders like me improve realism as much as possible on our builds. Thank you for your consideration.

I think we should be able to do more than 'set as main cockpit' in cockpit settings. it would be nice if we could set up things like:

-Aircraft type(air, ground, ship, etc...) so spawned AI/destroyer can choose which weapon to use, and player can use inferno instead of Air-to-air missile against ground crafts

-Autopilot mode types(if your aircraft is heli/VTOL, you can use hovering instead)

-Whether Activation 8 is on by default or not

-Whether dethrottling to 0% activates brakes or not (the current game does that)

-Whether pressing Brake dethrottles engines to 0% or not (this one, also)

-Crosshair types(green cross one is not always the best one)

-Whether Landing Gears are on by default or not

-Default targeting mode

-Default VTOL/Trim slider positions

Simple Planes is a great game, however it's accuracy in game physics and fluid dynamics isn't the best. Shippy456 states, "Due to my knowledge of very basic physics and fluid dynamics, I have become somewhat concerned about Simple Plane's physics and and it's drag model." WNP78 also describes, "Simple Plane's physics are definitely not as realistic as can be. They are pre-computed for each part at the start of the game and not updated if the craft's structure is changed. Parts which have no drag, when moved into airflow, will continue to have no drag. SimpleRockets2's drag model is more real-time, but at the end of the day, with all these things, it's about striking a reasonable balance between realism and not lagging out everyone's device." As you can see from these statements, I'm not the only one who is complaining about Simple Plane's current drag model. So, let's fix this! If you want an update on Simple Plane's physics, let's start voting! Thank you for your support!