1. Going smoothly, doing all right. Copacetic.
2. Proceeding quickly.
This expression may have originated in Scotland, where it's the title of a popular children's song. A song called "Everything Is Tickety-Boo" was recorded by Danny Kaye as part of the film "Merry Andrew".
This expression is heard more often in Canada nowadays. May have originated in the British military. Possibly related to the Hindi expression "tickee babu", meaning "everything's alright, sir". Some people spell it "diggity boo" or "tiggity boo".
Everything is tickety-boo, tickety-boo, tickety-boo...