Multi-Modal Ticket Booking App

I’m building a mobile hub that lets travelers book seats on buses, trains, and flights in one place. The app’s core job is fast, friction-free ticket purchasing, so I need a solid booking flow with secure payment-gateway integration (Stripe, PayPal, Apple Pay and Google Pay compatibility preferred)... (Budget: $750 - $1500 USD, Jobs: Android App Development, API Development, Backend Development, iOS Development, Mobile App Development, Mobile App Testing, Payment Gateway Integration, PHP, Test Automation, User Interface / IA)