the top speed of an F-35A Lightning II fighter jet is approximately Mach 1.6, which is around 1,200 miles per hour (1,930 kilometers per hour) at high altitudes. It's worth mentioning that the top speed can vary based on the aircraft's configuration, altitude, and other factors. The F-35A is a fifth-generation stealth multirole fighter designed for the United States and allied nations, and it's equipped with advanced technology to enhance its combat capabilities and survivability. For the most current and accurate information, it's best to consult official sources or the manufacturer's specifications.