Consider Norwegian has Tue/Thu/Sat flights from Austin (AUS) to London (LGW). RT in Premium Economy $1500-$1600 on such short notice. Or get 57.5k AA miles + $660 business class ticket on Thursday overnight flight from Austin via JFK (or on Wednesday from San Antonio) on aa.com, and return on Norwegian to AUS on Tue ($830 Premium Eco), it's daytime flight anyway.