Every 1-2 weeks this forum has a thread like this about mileage costs to a particular location for a particular month. It’s probably overdue for there to be a consolidated thread to dump them all into.

At any given time there’s places with high costs and others that are a good value, but things generally get especially tight around the summer and perhaps moreso now with high demand and high fuel costs. It helps to be flexible in time (both when to go and when to book) and location, and there are times when there’s nothing decent on the calendar but things generally fluctuate over time. As counterpoints I did transcon trips to Boston and NYC last month in flagship biz for 20-25K (for 2 pp each way)and have UK in Aug (and another trip for Spain in Sept) for 55-60K (biz, pp each way).