The bigger problem with air vs ground is currently you are annoying but hardly game changing, you probably get more points with spotting as air than attacking unless you are a super pilot.
Other stuff:
Only real sidearms of choice are tactical 1911 (balance of firepower, rof and blinding them) or the Supp G18 (automatic, supp won't affect bullet damage upto ~50M+). If you like CQC take the G18 although it's fairly high up the tree.
It's possible to fire the Co-Axial LMG between cannon fire on the Tanks - kill stuff. HMG can damage vehicles but it's RoF is horrendous, I'd avoid. Feeling
exceptionally balls out on the tank gunner? Have the enemy tank lined up, exit vehicle, fire RPG and get back in. You will survive this if the engagement range is >75M or so and they don't have autoloader, jump out just after the tank round hits/misses you.
If you're the last on your team and you're not an assault, hide. Doesn't really matter how you do it, back into a corner, jump off a building, prone behind a wall (they will spawn prone), you need position and backup.
The only real use for claymores is on rush defense (you can have more than one, resupply yourself) or seine where you can mine the steps. Even then I'd be hard pushed to call it useful, C4'ing around objectives in normal hidey holes is much more amusing. I believe it's affected by squad ammo perks?
Javelin has either a bug or design feature where you can be virtually out of LoS to fire without SOFLAM - you need about 3 pixels of the heat source within the enemy vehicle for it to lock and then to get the right missile-path simply aim bolt upright to fire (remember, same damage from each attack side).
To do the infinite Landmine turbo base defense lay them down, suicide then plant more. This is only really viable on a map like seine conq where you want to turbo plant on the C bridge/bridge between A&D. I'm not really a fan, a lot of people use thermals now but if you want ultra infantry abuse then plant mines on the pavements then get a mate to C4 the entire street walls. This can be incredibly hilarious on seine but the setup time is huge.
The grenade launcher on the IFV takes 3 to kill someone nearly always - damage is pretty bad if it's not direct. To be honest running around with your chums in the back and them running out to kill stuff is much easier.
Some silencers
don't work. Of note, Every engi gun bar AKS is bugged as is the mainstay assault (F2000, AEK). Unless you plan to flick to single shot firemode don't take heavy barrel in it's place, over 2 shots and the recoil gets questionable.
You can toggle tactical blind mode / laser - rebind it and use it if you want these on. If you're fighting >40M turn it off, it's just going to make people spot you easily.
If you're just starting the game I'd consider leveling the M416 (low recoil, decent RoF), SCAR-H (single shot selected, high damage, low clip) and M249. The 416 is an allrounder, the SCAR is just far too damaging and the 249 is captain easy suppress.
Don't shoot enemy medic/ammo boxes if you're first on the scene - it's a trap to reveal your position.
Perks - ammo is questionable with support existing (as is the grenade perk) but if your team aren't switched on it's viable, especially on conquest where your life will be longer. Support pretty much requires suppress, engi requires explosives unless your lifespan is measured in 20 second blocks. Flak is about on par with ammo for assault but realistically if you're going to get hit by an shell/mortar/explosive you'll seldom live anyway considering their damage. Sprint is OK but I only run it for my squad if we have everything else covered, find a jeep
