JustFly

Lots of reasons not to. A third party seller with a poor reputation. Buy directly from the airlines. Here is a link to one of many threads where people share their experiences.
https://www.tripadvisor.com/ShowTopic-g1-i10702-k10067902-Anyone_have_experience_with_Justfly_com-Air_Travel.html

What Carol now retired said. Book your flights directly with the airlines. No harm in starting your search with a site like Google Flights, Kayak, or Skyscanner to help see your possible choices.

The reality is that the airlines look at people using third party booking agents as low-lifes to begin with. This year there is still a big pent up travel demand from the pandemic and a shortage of flights and air crews likewise from the pandemic. Given those simple facts, the question arises: Golllly, what could possibly go wrong?

Book with the airline.

https://www.bbb.org/us/wa/bellevue/profile/travel-services/justfly-1296-1000084685

justfly is part of flighthub

Draw your own conclusion about doing business with them.