SQL Question.

I currently have two SQL tables One table called Waitlist and one Called Booking. They are not identical (waitlist contains more information than booking). They appear like so:

Waitlist:

#	Customer	Day	Timestamp	Flight
1	Joseph	2017-04-22	2017-04-22 16:20:33.178	F101

Booking:

#	Customer	Flight	Day
1	Timmy	F101	2017-04-22
2	Joseph	F101	2017-04-22

I would like to delete the duplicate data from waitlist (in this case the joseph entry).... I have tried the following:

DELETE FROM Waitlist WHERE Customer = booking.customer and day = booking.day and flight = booking.flight

I have also tried an INNER JOIN with no luck.

Please Help!!