Passengers traveling with Frontier Airlines ORD Terminal has the choice to utilize automated kiosks for faster processing or checking in at the airline's kiosks in Terminal 5. In order to conserve time, registering online is recommended as well. Visitors should arrive at Terminal 5 at least two hours before departing for domestic journeys and at least three hours prior for international flights because of the long screening stands by, especially during peak times.

 

For More : https://www.terminalfind.com/frontier-airlines/frontier-airlines-ord-terminal-ohare-international-airport/