As a flying character I'm trying to do some aerial recon/scouting and wanted to know how a perception check works (passive and active) while flying.
Aside from lightly/heavily obscured (PHB p. 183), what other penalties/factors are there?
Does height play a factor? (See note 2)
Does speed play a factor? (See note 1. If yes, assume moving at base fly speed (50ft)).
I'm planning on doing daytime scouting for mobs (aka targets/enemy units), both hidden and wandering (seeing if the group's path is clear or not), and anything out of the ordinary (campsites, lairs, caves, huts, anything that might require further investigation).
At night I plan to sky patrol (using ground level light spell, dancing lights spell). Also looking for other light sources (campfires, torches) that may be in the area/on approach.
If height makes a difference/you need a number, assume aerial scouting at just over 600 ft (say 625 ft). This is the magical number where long bows (all normal ranged weapons) cannot hit during the day.
For night patrols, assume just over 120ft (say 125ft), which is outside most night vision sight.
If possible please include any RAW that relates to this question.
Note 1: On PHB p. 182 there are penalties to passive perception checks for traveling at a "fast" pace (see table below). However this is for ground not flying (and I believe only passive checks not active checks).
Pace Distance Traveled per... Effect Minute Hour Day Fast 400 ft 4 miles 30 miles -5 penalty to passive Wisdom (Perception) Normal 300 ft 3 miles 24 miles — Slow 200 ft 2 miles 18 miles Able to use stealth
Note 2: My understanding (and would like input/confirmation of this) of RAW is that only lightly obscured (disadvantage on perception checks), heavily obscured (blocks vision), and possibly travel pace are the only factors in perception checks (both ground and air). Only LOS matters, thus the higher up I go the farther I can see/get perception (passive or active) checks on any items of interest (mobs, structures, etc.) not heavily obscured. Any limitation on this would be a DM house rule.