Swellow

Being the 3rd generation's Pidgey family equivalent, Swellow has nothing going for it. Piddling stats cannot support any moveset this 'mon has, even with double STAB.

Best PvE Offensive Moveset

• Wing Attack slightly outperforms Steel Wing for damage when factoring in STAB. 
• Aerial Ace or Sky Attack are your best bets due to Brave Bird's slow charge.

Best PvE Defensive Moveset

• Wing Attack or Steel Wing both don't matter when you're dead in one charged move while you're using Swellow. 
• Swellow won't get a charged move off but has the best chance at Aerial Ace. 

Wing Attack + Sky Attack and Brave Bird

Wing Attack takes advantage of STAB and greater energy gains to outperform Steel Wing in most cases. 

Sky Attack is the best Flying-type charge move in the game, which also makes it the primary charge move for Swellow. Because there's no significant perks to its other charge moves, Swellow actually doesn't need to unlock a second charge move at all. If you want to be as optimal as possible, Brave Bird can hit slightly harder if unshielded at the cost of more energy and worse energy efficiency.