Debatable Moeks. Early tier stuff gets researched pretty fast anyway, and you're better off learning how to fly and tank (and also how not to!) for a bit.
Maybe drop 50 Eagles or so on a couple of crew slots, get their vitality and reload speed up a bit.
Also, with tanks - only bother 'crewing' up your first 3 slots. That way you'll keep all your rewarded crew points into just 3 tank slots - which is the most you can take out in 1 battle anyway
No harm in hanging onto Eagles for a bit, until you decide if you want to get any premium vehicles either.
Maybe drop 50 Eagles or so on a couple of crew slots, get their vitality and reload speed up a bit.
Also, with tanks - only bother 'crewing' up your first 3 slots. That way you'll keep all your rewarded crew points into just 3 tank slots - which is the most you can take out in 1 battle anyway

No harm in hanging onto Eagles for a bit, until you decide if you want to get any premium vehicles either.