Only from UK to Europe - it was a package deal on an Eastern Med cruise in 2013.
But we did another cruise out of Venice in 2017 which was cruise only. I enquired about Celebrity flights and they were asking £600 return for the two of us - it's only a 2 hour flight. I booked my own flights with a low cost airline from London - into Milan, private transfer for 2 nights hotel in Milan, train to Venice, post cruise private transfer to Venice airport and flight back to London. That all worked out at less than £600!
But I wouldn't risk booking "on the day" flights just in case of delays. We're on another Celebrity cruise out of Barcelona in 2023 and I've done the same thing - 2 nights in Barcelona pre-cruise. We've been there a few times but love the city.
