You can buy gift cards directly from BitPay
by using their dedicated wallet. They don't offer Expedia, but they do offer Delta for booking flights, Hotels.com for booking hotels, and Princess Cruises for booking cruises.
I completely forgot about that.
Since OP appears to be in the EU they'll be offered a completely different selection of cards. Bitpay is showing me lastminute.com and Virgin for travel options. I think that might be Virgin holidays rather than airlines but I haven't checked.