How to convince DP we don't need to fly on holiday?

[AdultHumanFemale]

A few days ago DP received an invitation for the whole family to go and visit his friend who has recently moved to an old farm house by the sea in a southern European country. I am naturally grateful for the invitation, but:
We have recently committed to making some lifestyle changes to support the environment, and flying is definitely something we have both agreed ought to go. We don't fly a lot anyway, so not a massive ask.
DP has now gone all #makingmemories on me, and is going on about how it will be great for the DCs to have a continental adventure.
I can't seem to get through to him with the very same arguments which made him decide only earlier this year that it would be a positive, life-affirming choice to avoid flying. I am exasperated, he's coming up with some corkers, such as "If we don't get on that plane, some other family will..." and "We can just go greener in other areas of our lives this year." He's a bright guy, but seems to have had a brain transplant.
What can I say to convince him that we don't need a foreign holiday at the expense of the planet?

“What are his reasons for not wanting to train/drive it?”

I would have thought that was pretty obvious:

1. Time
2. Expense – flying is much cheaper than going by train
3. Tiring if driving. It is a big ask to drive that far, and not something I would want to do

"As a family we have been abroad several times since eldest DC was born 7 years ago, but only by ferry and then driving. It’s always been easy and enjoyable."

I think that might depend on whereabouts in the UK you live. Our nearest ferry port for Europe is Hull, but if we wanted to take a car ferry to Spain we would have to drive to the South or South West, which is not a drive for the faint hearted when it is busy. It once took us 9.5 hours to drive to Padstow.

@Ariela are you seriously suggesting the OP stops off in ROME en route to the south of Spain by train?!

Flying is the worst thing you can do to the planet so try and convince him to take the train.

What a depressing thread.

OP I think that the best course of action is to sell the Grand Adventure. I’ve been wary of flying for years as I have wonky sinuses and the pain is unreal. I’ve flown twice with dc and it has never been as comfortable or as much fun as ferries and trains. I’m only recently waking up to the environmental side (and frankly envious at how you dh is mostly on board with you) but even without that angle, I think flying is hellish with children. Is there anywhere interesting enroute that might tempt him to reconsider?

I’m not convinced at all that removing the offspring of people, with the compassion, vision and intelligence to put the planet before their immediate gratification, from the genetic pool is a wise strategy.

Meanwhile, in China, another 74 airports are due to open by the end of next year.

@Nakedavenger74
When I wrote my reply we hadn't established from the OP the destination as Spain, the only info I had was southern European, so Italy could have been the destination.

I was on your side at first OP but after your update about the dc I'm not sure.

No, I'm not one of those idiots people who say "well you've had dc so you may as well give up". None of us can give up no matter what we have done in the past.

But you convinced your husband to have not one but two dc, when he would have been happy with zero. So you know better than anybody, when you really want something, environmental considerations go right out the window. I'm not saying you should do the flight but you can't be surprised or not understand his behaviour as you've done the exact same thing yourself.

Are you vegan? This suggests that going vegan has a bigger positive effect than cutting flights, so maybe there is some compromise on food v flights possible?
www.google.com/amp/s/amp.theguardian.com/environment/2018/may/31/avoiding-meat-and-dairy-is-single-biggest-way-to-reduce-your-impact-on-earth

Buttered, I know, I do realise that. The element of surprise lies in the fact that DP seemed so keen to knock flying on the head, and it was totally in line with other adjustments he's made to his lifestyle for some time. We agreed to it together. Really recently. As a couple we tend to do our own thing, so I wouldn't have expected him to get on board with not flying if he wasn't that into it. There wouldn't have been 'consequences' for not agreeing to it in the first place, he could have just said "No, Adult, I actually want to hang on to flying, " and that would have been it.
The decision to have DC seems totally illogical now, in the face of what we knew 9 years ago when we started TTC, and a constant reminder that people do what they can, with the means they have. Having got that broodiness out of my system, I am now in a really good place to make good decisions about how I impact on the environment.
Pootle No, I am not vegan, and I know it would make such a great difference if more of us were. I have looked into it a lot recently and it seems the next logical step and there is so much good science to back it up. We eat a mainly vegetarian diet and the step to veganism (speaking for myself) wouldn't be too great really, we live in a city where veganism is quite popular so plenty of places to buy vegan products etc. Another one of those issues where the reasons to go for it are compelling and it is only a matter of personal resistance that I haven't done it.