Swift6
You would be surprised how flexible an airlines training machine can be regarding courses dates if required.
You are very fortunate that you had such an understanding employer. 99% wouldn’t be that understanding. That said I’m old school and even if I was on good terms with an employer, I wouldn’t leave them with such short notice. By the way what was the notice of resignation requirement in your old contract? Anything less than that, no matter how good a relationship you have with your employer is a most definite no no.