Not only do some squads favor certain aircraft, some seriously operate in only one aspect of the game -- fighters, bombers, or GV's. Some try hard to do all. Some just want buddies to fly around and get into furballs with. Some want to organize and take bases to win the war. Some squads are full of the young, silly and stupid. Some are made up of the older, wiser and more helpful. Some take historical accuracy seriously, some don't. Some fly loose, funny and friendly. Some fly seriously, strictly and even restrictively.
Some just want killers and don't care how you play or what you say, the badder the attitude the better. Some want people with friendly and compatible personalities regardless of current skill and will teach you the tricks and techniques of ACM and combat. Some squads are very large and some stay fairly small. What do you want?
The point is don't rush this as way too many new pilots do. If you don't want to be joining and leaving 2 or 3 different squads over the next six months, take the time to fight with and meet different people from various squads. Chat with them as you fight and if you like them, check out what squad they're with. Look for other squad members and watch what they do and how they do it. If you like them, just keep showing up to fight with them and/or ask to join some of their missions.