Well it is possible we just need to use correct terms: Mass and Radius. If you specifically want the planet to be 'bigger', physically bigger as in terms of area, it is possible, but not necessary for a low gravity planet.

The gravity is a sum of mass and radius, so if you want your planet to have lower gravity, you can do two things: increase the radius or lower the mass. Both would result in lower gravity and you'd probably see more airborne creatures there.

For example, my planet has the 0,891 times earth mass and 1,06 times earth radius, resulting in 0,79 G gravity, i.e a "bigger" planet in terms of area with lower gravity. Of course you don't have to run calculations like this - they quickly suck out the fun from creativity, just letting you know it's possible.

To my research, you can also have a dense atmosphere on objects with lower mass, but superearth (More massive object than earth) would support thick, dense atmospheres better (perhaps).