Yes, DBFZ does have a system of continuing and extending combos while in the air, but the weight of gravity will still pull everyone back down at some point.

There is one major mechanic that Extreme Butōden has that FighterZ doesn't - sustained aerial combat. It's ultimately not surprising, however, that Bandai Namco and Arc System Works would forgo the option to see Base Vegeta become Super Saiyan Blue mid-match because Dragon Ball Z: Extreme Butōden, often viewed as a precursor to FighterZ on the Nintendo 3DS from the same companies, also opted to keep them separate. Other lines of Dragon Ball games like the Budokai and Xenoverse series were able to use transformations widely and broadly over the years though those titles don't exactly have the same target audience a more traditional competitive 2D fighting game has. The team reportedly felt it would be too difficult to balance the game properly with such a mechanic, so they continued forward with the idea of separating out the fighters. 'If the character transforms, he will change and be completely different.'

Honestly there were several things, and as you said, transformation is one of the features we could not implement in the game,' stated Hiroki after being asked about features that didn't make the cut.

Dbz xenoverse 2 transformations