Premium economy shell seats on Japan Airlines. Premium economy is a travel class offered on some airlines. Positioning in price, comfort, and amenities, this travel class is leveled between economy class and business class. In 1991, EVA Air was the first to introduce Evergreen Class and had since become the first airline to offer this class of service in the world.
This sentence has two independent clauses. They are connected by and with a comma before it. The and and the comma are correct. However, adding a comma after thus is not correct because it is an adverb; the comma after it is not necessary. If thus is used as a conjunctive adverb (without and), a semi-colon and a comma are necessary.
Report Abuse. Commas are generally used when listing things, separating a sentence with the same thought, and before quoting someone. A list is pretty self explanatory, but an example would be: do this1, this2, and this3. I've heard around that you don't need to use a comma before the and, which is not true.