Overheating macair when videoconferencing

The MBA is not the best choice for long periods of videoconferencing. A desktop computer is better for that, especially if it's a primary use of a computer. If a portable is what you need, then a MBP with a fast CPU would have been a better choice. However, keep in mind that notebook computers, these days, have gotten lighter and lighter. That means less space and less metal for handling heat dissipation. Notebook computers are not replacements for desktops but too many users think that they are.

Of course, it will happen. What you are doing puts enormous stress on the machine streaming HD video. If the fans come on, and the computer doesn't shut down, then all is fine. Temps will rise well over 80ºC, depending on how long you do the streaming continuously. Buy a fan. Get some stick-on rubber feet to raise the rear of the computer an inch above the table. Do not use the computer on your bed or your lap. It's a notebook computer.