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.
1 Use a comma behind conjunctive adverbs when they appear at the beginning of a sentenceâs second clause. The only exception to this rule is that no comma is necessary if the adverb is a single syllable.  If a conjunctive adverb appears in the middle of a clause, it should be enclosed in commas most of the time.