Okay, expand that out a little. Bill Gates can fly into any country he wants and stay as long as he wants. Your typical coach flyer does not have that resource (visa constraints, return ticket constraints). He may have quite a few things in common with the upper-middle class but barely anything in common with the lower and poor class.
I think you're missing the point he's making. 200 years ago, it doesn't matter how rich you were - you could not travel across country in a couple hours. So the 'poor' of today are able to travel better and faster than the rich of yesterday.
Perhaps in 50 years time, everyone will travel how Bill Gates does now, and Bill Gates would travel even better. This would come about through better automation of air transport.
The argument is fairly simple: we can try to decrease the gap between Bill Gates and everyone else, or we can leave the gap where it is and focus on shifting the entire bar so far that the bottom rung of the future becomes higher than the top rung of today. This is the progressive idealist viewpoint of capitalism and stands in direct opposition to the socialist viewpoint. Historically, mixing the two together works best, and it's what we use: capitalism with high taxes. Unfortunately, localized competition for tax money is driving those taxes down and destroying the system while also using the taxes for short term and ultimately useless goals instead of long term infrastructure. In comparison, Norway is probably the country closest to 'correct' in how they are using the wealth generated from oil taxes - investing it in the positive return economy.
