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.
Use a comma to separate contrasting parts of a sentence. Example: That is my money, not yours. Rule 16a. Use a comma before and after certain introductory words or terms, such as namely, that is, i.e., e.g., and for instance, when they are followed by a series of items.ule 1. Use commas to separate words and word groups in a simple series of three or more items. Example: My estate goes to my husband, son, daughter-in-law, and nephew.