Define the research objectives: I would start by defining the research objectives, which could include understanding the current pain points and frustrations users face while booking flights, and identifying the key features and functionality that users expect in a flight booking app.

Identify the target audience: I would then identify the target audience for the flight booking app, which could include frequent flyers, business travelers, and leisure travelers.

Conduct user interviews: I would conduct in-depth user interviews with a diverse set of users to understand their needs and preferences when booking flights. I would ask open-ended questions and listen to their stories and experiences to gain a deep understanding of their pain points and expectations.

Gather data through surveys: In addition to user interviews, I would also gather data through online surveys to reach a larger audience and get a more quantitative understanding of user behavior and opinions.

Analyze the data: I would then analyze the data collected through user interviews and surveys to identify patterns and insights. I would look for common themes and pain points, and prioritize the findings based on their impact and frequency.

Synthesize the findings: I would then synthesize the findings from the research and create personas, which are fictional characters that represent the target audience and their needs, motivations, and behaviors.

Present the findings: I would present the findings from the user research to the design and development team to ensure that they have a clear understanding of the target audience and their needs. This information would be used to inform the design decisions and development of the flight booking app.

User research is an iterative process, and I would continually seek feedback from users and stakeholders throughout the design process to ensure that the flight booking app meets the needs of its target audience.