Highlights from their press release:

Business

• Boston → London: $2,980
• New York → London: $3,080
• Chicago or Atlanta → London: $3,830

Premium Economy

• New York → London: $1,283

Economy

• New York or Boston → London: $512
• Los Angeles or Austin → Rome via London: $463
• San Francisco or Seattle → Madrid via London: $437
• New York → Paris via London: $453

Checked the calendar for New York → London, and these prices stretch through Summer. There are multiple fares around the $3K mark in July and August (Business), and as low as $510 in May and August (Economy). You’re flying out on certain Tuesdays or Wednesdays but there’s some flexibility on when you return.