No-frills airline defective but let's go with it (5)
I believe the answer is:
basic
'no-frills' is the definition.
(I've seen this in another clue)
'defective but let's go with it' is the wordplay.
'defective' means to remove the last letter (the word is broken and incomplete).
'but' becomes 'bar' (both can mean 'excluding' or 'except').
'let's go' becomes 'sic' (I can't explain this - if you can you should believe this answer much more).
'with it' means one lot of letters go next to another.
'bar' with its last letter taken off is 'ba'.
'ba'+'sic'='BASIC'
'airline' acts as a link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for basic that I've seen before include "Fundamental; alkaline" , "Spartan" , "Simple, unadorned" , "Plain" , "Fundamental, forming a starting-point" .)