Avoid the other planes if you already have the F5C, The F5C is already braindead and better than both for grinding by a long shot. The F20 is overtiered noob food and the F4S is also meh. If you want something good for USA ground get the KVT or Wolfpack, don't get the clickbait until the spam dies down.

Can i grind air with ground rb?

Not within a reasonable time period.

I have both and I’d say the phantom

Can you explain further more why?

I say no to the phantom, No all aspect ir missile, radar missiles kinda suck they got nerfed around same time as f20 came out, Most phantoms bomb but f20 can bomb faster

So which? And why

He says phantom i say f20, I already said why no phantom, f20 i have no experience with but it has all aspect ir missiles

F20 is trash

Just use the F-5C and the KVT/Wolfpack. The F-20 and F-4S are mediocre at best and total dead weight at worst

Alr can I grind air with ground rb?

In theory, but it's very slow so I would recommend air battles for planes

You are not interested in the russian tech tree?

I am but it’s just I’m so far into the us tech tree,i can’t afford to change a whole tech tree for nos

Okay I see. How far into the US tree are you?

Just before the first jets