Flight of the Scarecrow... also known as: the level that can kill your run if you play on a PSP. Why? Well, let's talk about it.

The first portion of the level has you destroying a normal barrier with torpedos via Batwing and a silver barrier via towing floating mines with the Batcopter. The second portion of the level is very easy: you can just zoom past the enemies and go straight to the boss, which is where things get VERY VERY frustrating.

See, the way you beat the bosses of vehicle missions in this game is rather complex. In Two-Face Chase, you had to shoot Two-Face's truck, and tow it to the bat signal so the police can bomb it. In Batboat Battle, you had to tow the mines to Penguin's submarine, which can be a pain in the butt because the mine fly where you don't want them to go instead of where you DO want them to go.

In Flight of the Scarecrow, you have to defeat Scarecrow by grabbing three torpedos with the Batwing, switching to the Batcopter, hooking a tow cable to Scarecrow's plane, switching BACK to the Batwing, and firing a torpedo at the boss. In most of the console versions, this is a piece of cake, since you can add another player to join and have them use the Batwing so they can fire at Scarecrow.

In the PSP version however, you'll find that the method of beating Scarecrow is easier said than done. Why? After you hook up the Batcopter's tow cable to Scarecrow's plane, once you switch to the Batwing, Scarecrow escapes the tow cable. EVERY. SINGLE. TIME. And that is why Flight of the Scarecrow killed my attempt at speed running the game last night.

Can any of you guys give me some advice so I can beat this monstrosity of a vehicle level?

I do not know what advice i can give you. The best - in my opinion - will be starting game with order:
1-1
3-1
3-2
3-3
It will take you some time to do it to 3-3 but if you will do it 1-1, 1-2 etc. 2-1 2-2 etc. And then 3-1 3-2. etc. it will be end of the run so if you will do not get this good it will waste your 1-2 hours - I don't know how many time is it to speedrun on PSP. You can do it like3-1, 3-2, 3-3 but at the start of 1-1 you can go to Batcave. If you running Replay Story (not story) you can just start from 3-3 and then do what you want. You can also practice 3-3 boss fight to be the best 3-3 boss fight PSP player if you want to. I would maybe have LEGO Batman: The videogame on PSP so maybe i will give you some advice. I'm not a PSP player so i can not give you advice to how to play good on PSP, i can only give you some tips how to not waste 1-2 hours (again - I do not know how much time is speedrunning LEGO Batman: The videogame on PSP is).