The 2015-2017 12" Macbook was an ultra-thin fanless machine that was delightfully portable but was basically unusable for anything more than basic web browsing. It'd burn my thighs just watching Youtube.
The 2021 M1 Air is a slightly chunkier fanless machine that runs circles around Intel laptops with desktop-class processors, at lower cost and up to triple/quadruple the battery life. It's unlike any Intel laptop you'll find on the market today.
Apple deserves plenty of flak for their laptop design decisions (crappy webcam, fat screen bezels, port selection...) but the M1 is probably the biggest improvement to laptop performance in a decade.