FlightAware sued Kalshi, alleging the prediction market used its flight-tracking data without permission to run flight-cancellation betting markets and falsely presented FlightAware as a partner.

The suit claims Kalshi violated FlightAware's trademark and contract rights, and seeks a temporary restraining order plus injunctions. FlightAware warns the markets could strand travelers, disrupt airline operations, and even push people toward unsafe actions.

It piles onto Kalshi's mounting legal troubles, from a New York illegal-gambling suit to blocked sports contracts in Washington and Michigan.