The Unsuspecting Aviation Side Hustle Making $4K/Mo with SaaS

Table of Contents

• 🚁 From Side Project to Lifesaver: Ernst Mulders' …

  • 🌱 The Early Days: Always Launching

  • 💡 From Demo to Lifesaver: Building AirAssist

  • 🚀 Driving Growth with User Feedback

  • 💸 Monetization: Building a Freemium Model

  • 🏅 Maximizing Visibility: App Store Optimization

  • 🌍 Scaling to New Markets: Rinse and Repeat

  • ❤️ AirAssist in Action: Saving Lives

  • 🧘 Balancing Indie Hacking and Life

  • 🎯 Key Takeaways: Do the Unexpected

🚁 From Side Project to Lifesaver: Ernst Mulders' Journey with AirAssist 🚁

Meet Ernst Mulders, a 33-year-old developer who has been building side projects since he was a teenager. What started as a way to improve his app development skills led to the creation of AirAssist—a project that not only became his most successful product but also ended up saving lives. Ernst takes us through his unexpected journey in creating a life-saving tool.

🌱 The Early Days: Always Launching

Since the age of 16, Ernst has been building projects on the side of his studies and later, his full-time work. His passion for product development has driven him to launch multiple products on platforms like Product Hunt and various app stores.

One of his earlier projects? A simple time-tracking software that earned him money—unexpectedly. But that experience showed him the importance of combining product design with monetization. Along the way, he also launched a travel website called Seven Places, which used Instagram data to recommend new locations. Sadly, a policy change on Instagram ended that journey early, but it was a learning experience for him.

💡 From Demo to Lifesaver: Building AirAssist

Ernst’s breakthrough came when he shifted focus from making money to just building something fun. AirAssist, originally created as a learning tool for working with React Native, has grown into a real-time tracker for emergency services helicopters. What began as a simple project displaying a few helicopters quickly morphed into a tool tracking over 550 aircraft across multiple countries.

The app caught on, and before Ernst knew it, he had users requesting features that he had never anticipated, like real-time incident notifications. One hospital even contacted him to say they were using AirAssist for critical operations.

🚀 Driving Growth with User Feedback

One of the keys to AirAssist's growth was user feedback. From the start, Ernst encouraged his audience to send suggestions, which led to unexpected use cases. Hospitals and emergency professionals began relying on the app, and Ernst quickly realized its potential.

Feedback also drove international versions of the app, especially in the U.K., where real-time notifications beat traditional news sources in delivering incident updates.

💸 Monetization: Building a Freemium Model

At first, monetization wasn't even on Ernst’s radar. But as server costs grew, he introduced ads and then later, a paid version of the app. What started as a simple €2.99 option to remove ads quickly grew into a subscription model offering different tiers. Users embraced the new pricing model immediately, validating Ernst’s freemium approach.

And when he doubled the prices last year, he was pleasantly surprised that users continued to pay without hesitation. If you're thinking of launching a product, check out some tips on pricing strategies to make sure you're on the right track!

🏅 Maximizing Visibility: App Store Optimization

One secret to AirAssist's success was App Store Optimization (ASO). In the Netherlands, people were searching for P2000, the public messaging network, so Ernst strategically included it in the app’s name. This tactic helped him drive organic downloads, without spending heavily on marketing.

Expanding into new countries like the U.K. and Germany has proven more difficult. There’s no single term driving searches, so word of mouth and social media have played a bigger role in growing the user base internationally.

For developers looking to improve their own app's reach, check out some ASO best practices to maximize visibility.

🌍 Scaling to New Markets: Rinse and Repeat

Off the success of AirAssist, Ernst expanded into new verticals. Waterbomber, another real-time tracking app, focuses on firefighting aircraft. It’s now available in the U.S., Europe, and Australia.

Scaling these apps has come with its challenges—particularly managing radar coverage in large countries like Canada, where firefighting aircraft may only appear intermittently. But Ernst continues to push forward, manually adding new aircraft to the system and keeping the service as accurate as possible.

❤️ AirAssist in Action: Saving Lives

The most fulfilling part of AirAssist has been hearing from professionals who use the app in life-saving scenarios. Ernst has received messages from police officers and fire departments in various countries, sharing stories of how AirAssist has saved crucial minutes during emergencies. One officer even credited the app with directly saving a person’s life by accelerating their response time.

🧘 Balancing Indie Hacking and Life

For Ernst, indie hacking remains a passion that fits into his busy life. He still works a full-time job but dedicates around 10 hours a week to maintaining his apps. While he eventually hopes to go full-time, he’s content with the balance he’s struck for now.

If you're an aspiring indie hacker, take note—building side projects while balancing life and work is possible!

🎯 Key Takeaways: Do the Unexpected

If there’s one lesson from Ernst’s journey, it’s to expect the unexpected. AirAssist was never meant to be a money-maker, yet it’s his most successful app to date. Sometimes the simplest idea can become the most impactful.

And remember—your product doesn’t have to be perfect at launch. Keep it simple, get feedback, and iterate. Your users might surprise you with how they use your app in ways you never thought possible.

Closing Commentary
Ernst's journey with AirAssist is a fantastic example of how even the smallest side project can grow into something life-changing. By focusing on user feedback, staying flexible with monetization, and not being afraid to take a chance on an idea, he’s built something that matters.

If you’re working on a side project, what’s stopping you from launching? Keep it simple, listen to your users, and see where the journey takes you.

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Cheers,

Matt