It honestly isn't that crazy of a request. Assuming this is a chartered jet, the liability is already factored in to the cost of the charter. the cost in extra fuel for two people flying 1,000 miles is only about $120. Even security would be "meh". We take a charter to various races throughout the year (never miss Talledega). I can't tell you the number of times we've taken a stranger with us (simply because we liked them when we met them), and it's never been an issue... they're just excited to be flying on a corporate jet (it is cool as fuck).