TL;DR: Noctowl is a very tanky generalist prestiger and it packs a punch against Snorlax.

Some long-time players may remember the times when Pidgeot with Wing Attack / Hurricane was considered the best commonly available prestiger. In particular it was excellent against Snorlax with Lick and/or Earthquake.

Then came Gen2 with the movesets overhaul, Pidgeot can’t learn Wing Attack anymore, Hurricane has been outclassed by other charge moves and Wing Attack has been slightly nerfed in both duration and power.

So let me introduce to you the new King of Flying Prestigers: Noctowl!

Noctowl’s typing is Normal/Flying, which makes it automatically resistant to Ghost (e.g. Lick), Grass (e.g. Solar Beam), Ground (e.g. Earthquake) and Bug moves, and only vulnerable to Electric, Rock and Ice.

Its best moveset, Wing Attack / Sky Attack, has a weave DPS of 21.7 (92% of the max possible neutral weave DPS) and it is neutral or Super Effective against everything but Electric, Rock and Steel.

But above all, Noctowl has the 8th-highest Defense x Stamina / Attack2 ratio among Pokémon capable of reaching 1300 CP at level 30:

Rank # Tanky prestigersqrt (D x S / A2)Max CP (level 30)

According to my CP efficiency calculator, here is the relative performance of Noctowl (in terms of combined time and revive efficiency) against some of the most common defenders gym sitters:

 DefenderDefending movesetNoctowl performance Benchmark
VaporeonWater Gun / Water Pulse 57%Tangela / Parasect
SnorlaxZen Headbutt / Body Slam 65%Machamp
SnorlaxLick / Heavy Slam 70%Poliwrath
SnorlaxLick / Earthquake 87%Poliwrath
ExeggutorConfusion / Seed Bomb 60%Scizor
DragoniteSteel Wing / Outrage 51%Cloyster

These are already pretty good numbers, especially against Snorlax. If your main concern is prestige per revive, however, that is where Noctowl shows excellent performance:

 DefenderDefending movesetNoctowl performance Most resilient prestiger (excl. Chansey/Blissey)
VaporeonWater Gun / Aqua Tail 68%Kingdra
SnorlaxZen Headbutt / Body Slam 73%Forretress
SnorlaxLick / Heavy Slam 81%Lanturn
SnorlaxLick / Earthquake 99%Umbreon
ExeggutorConfusion / Seed Bomb 78%Skarmory
DragoniteSteel Wing / Outrage 74%Steelix

These rankings are done with a 0%-70%-30% dodge setting, i.e. dodge only specials and more likely to dodge if using a non-Super-Effective fast move (because it doesn’t delay the “Defender used Charge Move” message).

Anyway, Wing Attack is fast enough to allow flexibility when dodging the defender’s fast moves, so the rankings are similar in a dodge-all scenario.

Complete moveset ranking:
1) Wing Attack / Sky Attack
2) Extrasensory / Sky Attack
3) Wing Attack / Psychic
4) Extrasensory / Psychic, Wing Attack / Night Shade
6) Extrasensory / Night Shade

Even if only #1 and maybe #2 are worth keeping, whenever I evolve a Noctowl I use it at least once in order to save a revive, just because of its tankiness.