There are really two different approaches to aerial gaming: the "dogfight" game and the "air battle" game.
Many popular classic air games are very much "dogfight" games because of their focus on individual plane and pilot characteristics: Mustangs & Messerschmitts, Check Your 6, Blue Max/Canvas Eagles, Mustangs, etc. A dogfight game is typically for a small number of planes per player (maybe only 1!) because it's all about maneuvering and shooting and outwitting the enemy, and it takes a lot of time and energy to manage each plane. For a game in this context, I find spotting rules completely inappropriate. It's a very poor gaming experience to be stuck as the "sitting duck", watching the enemy line up a perfect shot and depending on Lady Luck to spoil the shot. Miniatures gamers want to roll dice *and* move miniatures, not just remove them from the table, so in my opinion, the scenario should begin with all players aware of each other and able to being maneuvers on the first turn. Where they would be a fun equalizer or tactical puzzle, ambush situations can be represented in the setup conditions (e.g., the bouncing planes start with positional advantage).
An "air battle" game is a more expansive concept, aimed at playing fast and (usually) getting more planes on the table, by abstracting the individual maneuvers and shots, and focusing more on the overall mission. Some newer air games (Bag the Hun, Blood Red Skies) and many of the aerial rules included in naval games have a more "air battle" focus, typically abstracting individual plane maneuvers or just ignoring them altogether, to better focus the players' attention on the objective(s) of the mission and/or the importance of coordination and mutual support. In such a game, esp. with each player controlling multiple flights or even multiple squadrons, it makes perfect sense to try to model aerial ambushes in the course of the game. Bounced victims were a perfectly normal part of aerial combat, and might even be a critical force equalizer in an imbalanced theater (e.g. the 1941-42 Western Desert campaign).
There's no bright line between these two concepts, it's more a matter of focus and personal taste, and many rules try to cover both foci to some extent. However, I think it's a good idea to evaluate the main focus of the game before determining the appropriate use of spotting rules.
My only "recommendation" is a negative one: don't use the spotting rules in CY6.
I play a lot of CY6, and I find the spotting rules to be a waste of time, and poorly written too. I already mentioned that I consider CY6 very much a "dogfight" game, with a single flight of 2-4 planes about the maximum burden for any one player. The spotting rules pretty much require planes to fly straight and level until they "spot" an enemy, which can result in planes being left completely out of the fight. CY6 is a Hollywood-style dogfight game, not a hyper-accurate simulation for recreating the minutiae of pilot attrition in combat situations, so I really don't care if this kind of encounter is "realistic"; it's no fun in play.
I am still on the lookout for an "air battle" style game I like to play, so I don't have any personal recommendations. Lots of people enjoy BTH and BRS, so they're worth a look.
- Ix