acro, angle, horizon, air mode?

There are 4 flight modes that you can activate on the typical programmable flight controller:
- angle mode (self level)
- acro mode (more manual control, no self level)
- horizon mode (a mix between the above two. It flips and rolls, but also auto levels.
To fly a quad in "manual", one of the above modes need to be enabled. On some flight controllers, if neither angle nor horizon is activated, acro is the default.
Acro mode is the least challenging for the hardware, but the most challenging for the pilot.
Angle mode is generally considered easier to fly. Especially on micro quads.

In addition to selecting one of the three above modes, you can activate "air mode" in addition.
It will keep the props spinning even at zero throttle, so you wont loose control by one prop stopping. You need to deactivate air mode quickly before landing or while crashing!