Information from the written clues.
1. Thomas couldn’t have flown on Saturday if he flew earlier than Yvonne.
Yvonne couldn’t have travelled on Monday if thomas flew earlier.
2. Doreen couldn’t have flown on Monday if she travelled later in the week than someone.
The Manchester flight couldn’t have been on Saturday assuming Doreen travelled at a later date than the flight.
If Doreen flew later than the Manchester flight, she didn’t go to Manchester.
3. Mike didn’t go to Glasgow and whoever went to Birmingham didn’t go on Tuesday or Wednesday.
If Mike didn’t take the Tuesday or Wednesday flight then he didn’t got to Birmingham.
Mike didn’t go to Glasgow, the Glasgow flight is on Monday, therefore Mike didn’t fly on Monday.
6. If Steven took either the Manchester or Belfast flight, he didn’t take the other flights.
7. Babs didn’t fly Thursday and couldn’t have taken the Saturday flight if she travelled earlier in the week than someone, she also could not have travelled on Monday if she travelled the the day after the Cardiff person.
Steven didn’t fly on Monday because Babs flew earlier in the week than him.
Babs earliest possible flying day is Tuesday, therefore Steven, who travelled later than her, didn’t fly on Tuesday.
If Babs flew the day after the the Cardiff flight, the Cardiff flight didn’t go on Saturday.
The earliest Babs can fly is Friday (see 7), so the Cardiff flight can’t be on Friday.
Bab’s must have gone to Birmingham, so the Birmingham flight didn’t go Monday, Thursday or Saturday, which only leaves friday.
If Stephan travelled later he had to have flown on Saturday.
If Babs flew the day after the Cardiff flight then the Cadiff flight was Thursday.
If Stephan flew on Saturday he went to Belfast.
All clue eliminations say:
Manchester flew on Tuesday
Inverness flew on Wednesday
Glassgow flew on Monday
Cardiff flew on Thursday
If Doreen tavelled later in the week than the Manchester flight and the Manchester flight went on Tuesday then that only leaves Wednesday that Doreen could fly.
That cancels Wednesday for Yvonne which leaves only Tuesday for her flight.
Which means Thomas could only have flown on Monday.
The Tuesday flight wasn’t to Glasgow or Inverness, which means Yvonne went to Manchester.
The last puzzle is Dorren and Thomas and the Glasgow and Inverness flights.
The Wednesday flight didn’t go to Glasgow, Doreen flew on Wednesday, so she must have gone to Inverness.
Last one, Thomas had to have gone to glasgow.