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 give a lot more credence to this answer).
'with it' says to put letters next to each other.
'bar' with its last letter removed is 'ba'.
'ba'+'sic'='BASIC'
'airline' is the link.
This may not be correct. 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" .)