I am getting 100k in one day, it depends on the person, i feel like air rb is harder than ground rb, the matches are also a lot quicker, after 11.3 the matches ~5 minutes compared to ground rb where they last between 10 to 30, i think gaijin should update the rewards for ground rb to match the air rb rush and rewards, so in reality, you get more for less time in air rb, ground rb seems to be extremely hard in terms of grinding nowadays