To be the only one to upgrade on a group trip?

You are presenting the question the wrong way round.

It's not are you unreasonable to upgrade but are you unreasonable not to pay more to downgrade.

If it was an extra cost then I can see how people might think 'just sit with us'.

But it seems madness to pay more for less.

Present it this way and say you'll use (some of) the difference for drinks at the airport, lounge access or some other token..

I would not begrudge anyone an upgrade if they got the chance, it's so much better. I would love this for my sister. Why not?

And my (same age to yours) kids wouldn't mind At All. They know they are much more hardy and flexible than me (eg bendy and can sleep on a washing line). Obviously I wouldn't leave little ones.

Maybe I would measure it by the length of the flight - 5 hours plus deffo worth it. But really, if your upgrade is cheaper than the regular economy, it seems like a no-brainer (especially since you are likely paying for the kids holiday anyway?)

If you sister is laying for the trip then it would be a bit rude to pay for upgrade. But if your paying for your family's flights then why not especially if you are saving money. If you can afford to buy dinner one night on the holiday for your sister and her kids to 'compensate'

You would bring everyone snacks from first and would be swapping seats with other people? Like what, you would stuff your pockets with snacks or grab a tray of sandwiches to carry across the plane? Do you realise how this looks??

Lmao okay, clearly you’re a lovely person. If a family member of mine had this, I’d be pleased for them.

If I was the family I wouldn’t want you to miss out on the upgrade and pay more to sit in economy

Go for it! No issue for anyone else. No caring responsibilities or leaving anyone else on their own.

These tickets are not unlimited and cannot be bought for just anyone and everyone. If they could, the OP would be suggesting they be bought for her entire family. The staff member can only buy a limited amount a year and only for those named on her travel pass. Hence why the OP is the only one who can benefit from this. It is also a standby ticket. Meaning if they plane is full of paying customers, the OP gets bumped from it and has to wait for the next plane to try again.

Was meant to quote @Applecup for this post

This with bells on. The airport stuff and the flight are part of the trip. If you're in some special lounge they are excluded from and then you have a fabulous flight whilst they are in economy then you are absolutely a 'cunt' just as you have self-described.

No wonder it’s so expensive to fly when free tickets are being given out to all and sundry.

I’m assuming you’ve got a family WhatsApp group? i’d be writing that I’ve spoken to my friend and if she books it it will be loads cheaper, plus it’s an upgrade.
because it’s a better seat/area happy for someone to have it on way there anyone interested?

Then have it on the way home when you’ve all had enough of each other :)

As there are no little kids it seems fine to me. I wouldn’t mind at all if someone I was travelling with did this.

Yeah I’d do it and I bet each of them would given the chance.

So you'd leave your sister with all the children? Albeit teen/adult ones? In that situation absolutely not.

It’s a standby staff travel ticket. Not a normal purchased ticket. So it’s that not easy unfortunately.

Upgrade both ways, your sis gets one way you get the other?

Honestly if it were my family they’d be encouraging me to go first class. I can hear the banter from my brothers now. Do it OP, based on who you’re traveling with there should be no animosity

Hello Kirsty Allsopp- how are things? Interesting username.

Depends on the length of the flight. Not really worth the bad feeling it could cause for a short haul. If going on a flight 12+ hours it is probably worth it!

Given Op's comment about potential stand by ticket and not getting that flight ended with a " ha ha" I think its safe to say, she would choose to leave her sister and kids to get the original flight and op wait for her better class seat to be available on another.

Which is a bit crappy when travelling with family, especially if some of those family are your own kids.

When travelling on someone’s staff travel you must behave in a professional way even if you are not staff yourself. There are rules when using staff travel so I can’t see any of this being a good idea. If it gets back to the staff friend who’s name she’ll be under it won’t look good on her.

It’s definitely a stand by ticket. So it all depends on how busy the plane is and if upper class is full, would she choose to be bumped down to economy (if that isn’t full) or would she choose to try again on the next flight (and risk the same thing happening again).

@NeedSleepNowww yes you can buy a cheap economy ticket instead (which will be even cheaper than the upper class one). But it will still be standby which still means the risk of not getting on.

Do it and share.
Bring everyone snacks from first. Then, let your husband have a snooze. You can swap, you know.
If you are awake , let someone sleep in your spot.

Are your family the type of people who would have an attitude about it or would they not care?

I wouldn't do it and I'd be secretly hurt if my sister did this

I do think generally, when going away with someone and meeting in the airport to travel together , you actually travel together. Not pretty much imply"actually I'm entitled to a much better seat than you lot of see ya suckers"

Now you are saying there is a small chance you would end up on a stand by ticket and arrive later than all of the others. Sorry, I think that is selfish and unreasonable