The Pro Lite has been discontinued for a long time, there is just a large stock of them out there and that's why they're sold at around $20, dealers want to get rid of them. This does not mean it is a $20 knife or was intended to be a $20 knife. With that being said...
The Pro Lite and Air Lite are NOTHING alike. The Air Lite is twice the cost of the Pro Lite, not three or four times.
- Pro Lites are a budget knife, plain and simple. Plastic handles, 4116 steel, $49.99. They feel generally pretty cheap but perform pretty considering their materials and price.
- Air Lites are a mid range knife. Beautifully machined G-10, AUS10 which is far better than 4116, $99.99. They feel like a well built solid knife, better than the Broken Skull in my opinion. Quality feels like it compares to the Lawman's and Recon's, etc.
I think people are thinking that because they share the "Lite" name, they're somehow related. It's not an upgraded Pro Lite, it's a brand new knife in both design and manufacturing. The Pro Lite was discontinued to be replaced by the Working Man. The Working Man was discontinued this year so we decided to get away from the Pro Lite/Working Man series entirely. They have similar dimensions because this is the most popular size option, the two most popular blade styles requested, and upgraded materials like everyone always asks for.
In my opinion, it's 4x or 5x better than the Pro Lite. Honest opinion now that I've been EDC'ing it for two weeks out of the month long experiment I'm running.