Ascendant Step Questions

I was wondering, when using Ascendant Step (9th lvl Warlock invocation) in combat, if you would be able to cast spells while suspended in the air. Along with this, I was wondering if a creature (friend or foe) would have any sort of advantage or disadvantage towards their attack rolls against someone suspended in the air. Furthermore, would the suspended individual have any sort of advantage or disadvantage towards creatures they target?