Hour one to five : The basics that you must know on arrival in order to avoid confusion ​​​ 

1. "How ya going?"

Common greeting asking how someone is

2. "Oi, mate" 

A way to grab your friends attention or to say hello

3. “Heaps good”

Excellent

4. “Arvo” 

Afternoon

5. “I’m buggered / knackered”

I’m exhausted

Hour six to 10 : very common, everyday words

6. “Good on ya” 

Well done (often said ironically)

7. “Maccas”

McDonald's

8. “Cuppa” 

A cup of tea

9. “Devo”

Devestated

10. “You beauty”

Hell yeah!

Hour 11 to 15 : Sleep deprivation starts to kick in around this time of the flight. However, I guarantee you people legitimately use these words

11. “Waffling on” 

Talking too much

12. “It’s pissing down”

It’s raining heavily

13. “Yeah nah" and "Nah yeah”

No and Yes

14. “Bloody ripper”

Really Awesome

15. “She’ll be right”

She will be OK (often used to refer to anyone and anything)

Hour 16 to 20 : Unlikely to hear often but very fun to say

16. “It’s chockers in here”

It is very busy or full

17. “Trackie dacks”

Tracksuit

18. “Heckers” 

A lot is happening

19. “Chuck a uey”

Make a U turn

20. “Such a dag”

Someone with no style however is usually like for that (my sister for example)

Hour 21 : The end is near

21. “Dusty” 

Probably how you feel after a 21 hour flight, however more commonly used to refer to someone who is hungover