There is a very famous fanchise Sushi restaurant , Uogashi Nihon ichi existing.

Although it is  franchise, full-fledged sushi cook are there. therefore, you can eat true Sushi @ Haneda International airport. Sushi in the picture have only 6 pieces but the price is almost 600 JPY. cost effective.

初国際ターミナルな羽田。勝手がわかないなりにも、寿司食べたいと思ったら、魚河岸日本一発見。

お腹もすいてなかったので、一番小さい寿司。600円は結構お買い得。ちゃんとした板前さんだったし。