Is your set of types of emails (Confirmation Email, Cancellation Email etc) small enough? If yes, in a first step, try to do a simple classification into types of email. Then in the next steps, you can apply different tools based on the type of email.
For the rest, I think it's best to use regexes, even if it is tedious. You might want to look at UIMA TextMarker to quickly implement your regexes/rules.
- Ticket Number: regex
- Flight Number: regex
- Departure Time, Arrival Time: regex
- Passenger Name: Person NER (here a uima example) (or match with email To: field?)