I was a public discussion forum local to me a couple years ago, and the speaker put up 5 households and we were to rank them by which we thought had the highest carbon emissions.
The results had the highest ranked household as the 'eco travel' couple, largely due the greenwashing by companies having led them traveling more frequently. That surprised a lot of people at that event. I also think a lot of these types of events including the People's Emergency Broadcast showings, the focus on individuals around this obscures the picture. There is strong data that over 70% of harmful emissions are from 100 companies, many of them government backed companies, so even has someone who hasn't flown in decades, I get why so many feel their drop in the bucket is meaningless.
Large businesses need more actual pressure on their sustainability practices, not lip service, which would likely lead to a changing in balance of online to in-person meetings. The includes British governments - I'm a civil servant, I've seen how sustainability is largely framed in costs (like how every page printed is a charge) rather than really much data on the environmental impact of using pages printed vs having screens.
Leisure, as many mentioned, UK needs better transport options. I mean, it is ridiculous as someone living in the Midlands that it is far easier, cheaper, and more accessible for me to fly to most of Europe or North America than it is for me to take a train or bus to Inverness. I medically cannot drive. I've been trying to plan that trip for months. Part of the reason for this dream trip is small businesses in Inverness who will take couples and small groups out into the nearby dark sky area to go star gazing, and I've largely ended up feeling hopeless more than a few times almost entirely around transport. It's become a family joke that we'll just wait until my 17 year old who is keen to drive to be able to afford to do so.
I definitely don't approve of excessive business travel but I assume employees don't have much leeway to say no if travel is expected of them.
Then the focus should be on businesses making it required to travel, just like the focus on carbon emissions, water usage, and so on should be on the large businesses and governments having the largest impact. The company and events should be viewed as the very frequent flier rather than the individual, we should have data on that to have real context.
As others mentioned, it's ridiculous to have a global summit on climate issues involve people flying all over the world when there are far less carbon heavy options for global communication.