Correction: You literally needed a lap (or a pull-down table larger than the ones on airlines) to operate a lap-top outside of the office.

The notebook was as much of an incremental size difference to a laptop as a netbook is to a notebook today. That's why they were called notebooks. You literally needed a lap (or a pull-down table larger than the ones on airlines) to operate one outside of the office. When notebooks first came out, they were actually thought as being "hardly" bigger than a notebook. Granted, the screens then were smaller (my first notebook had a 13" B&W LCD screen), so they were smaller than many of the notebooks on the market today, but they were a quantum leap size-wise when they first hit the market.