Since Transavia is a Dutch airline and the original arrival airport was Amsterdam, EU passenger rights apply. These state that:

“The airline must offer you, on a one off basis, a choice between:
– the reimbursement of your ticket and, if you have a connecting flight, a return flight to the airport of departure at the earliest opportunity
– re-routing to your final destination at the earliest opportunity or,
– re-routing at a later date at your convenience under comparable transport conditions, subject to the availability of seats.”

The rules also state that “If the airline does not offer you the choice between reimbursement and re-routing but decides unilaterally to reimburse your original ticket, you are entitled to an additional reimbursement of the price difference with the new ticket (under comparable transport conditions).”

See: https://europa.eu/youreurope/citizens/travel/passenger-rights/air/index_en.htm#reimbursement-cancellation-1

One of the major reasons that travel insurance have certain exclusions about reasons for travel delays or cancellations is that often other rules will apply that don’t make it necessary to use the insurance in the first place.

If you booked this ticket with a credit card, check if that came with trip delay or cancellation insurance as well. In terms of insurance, a diversion of a flight is considered a cancellation, so you may actually have more rights than you think.

Sorry to hear that Jeremy and it’s a shame Transavia did that. I don’t want to be the “well, actually” guy but I think this may be an example of not knowing what the insurance will cover. I don’t know about your policy, but my Heymondo policy only covers expenses for 12+ hours of travel delay (in specific cases). Eindhoven is an hour by train from Amsterdam. If in doubt, a quick message to Heymondo would confirm whether you could count on expensing your new plane tickets. When trying to claim for something that’s not covered the situation will be the same regardless of insurer.