Many subway cars or train cars have seat configurations like the one submitted by the company Heinkel Group for this year's Crystal Cabin award for airplane design. People are responding very loudly and negatively in response to this design, which was originally intended to bring families together during flights. The idea of staring into someone else's eyes for the duration of a flight is unappealing to many.
Although designed for privacy and comfort during flights, many consider the lack of leg room problematic as well. You can read more about the proposed design here.