влететь - to fly in also used in the phrase: влететь на бабки (to face the situation when you must part with some money , i.e. you borrowed money but something went wrong and now you ought to pay but you don't have any money. (бабки = slang. money).

In this case you may say Я влетел на бабки)
влететь could also mean to crash into, to collide with smth, i.e. Я ехал по заснеженной дороге и влетел в столб. Чудом остался жив.

залететь - to fly in, but in this case this bears some incidental character, i.e. камень залетел в окно - the stone flew in through the window.
also you can say залететь далеко (Я бросал камни, но они не залетали далеко)

More examples:
Я залетел на бабки - Yes, the meanins is the same as in я влетел на бабки.
Я залетел к вам на пять минут - I came to you for only five minutes. (That means I'm in hurry and have to go soon).

And of course, залететь means to get pregnant.
Моя подруга залетела, теперь её папа хочет, чтобы я на ней женился.
(My girlfriend got pregnant and now her father wants me marry her)