The S&P 500 Growth index has fallen sharply in recent months, weighed down by fears surrounding high inflation, geopolitical conflict, and rising interest rates. Even so, the index is up 260% over the past decade, easily outpacing the 198% return of the broader S&P 500. That data makes a strong case for owning at least a few growth stocks, especially if you still have plenty of time before retirement.

With that in mind, Airbnb (ABNB -1.68%) and Paycom Software (PAYC 1.63%) recently posted impressive quarterly results, and both stocks look like smart long-term investments.

Here's what you should know.

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Image source: Getty Images.

1. Airbnb

Without owning a single rental property, Airbnb has turned the travel industry upside down. Its platform helps guests book rooms by crowdsourcing real estate from hosts in thousands of cities around the world. That asset-light strategy makes Airbnb more agile than traditional hotels, supercharging the network effect that powers its business. In other words, the company can quickly and cost-efficiently onboard new hosts, and each new host adds incremental value for every guest (and vice versa).

Better yet, Airbnb can offer guests a far more immersive experience than any hotel. Its platform lists everything from secluded cabins and rustic cottages to trendy apartments and suburban homes. It even lists thousands of unique lodging options like yurts, castles, and treehouses. Airbnb also introduced flexible search parameters last year, meaning its platform can make personalized booking suggestions when people are flexible on dates and destinations.

With travel and tourism on the rebound, Airbnb posted impressive financial results in the first quarter. Nights and experiences booked jumped 59% to 102 million, revenue soared 70% to $1.5 billion, and free cash flow (FCF) skyrocketed 96% to $1.2 billion. Better yet, gross booking value climbed 67% -- as a leading indicator of sales, that points to solid growth in the coming quarters.

Going forward, Airbnb puts its market opportunity at $3.4 trillion, which leaves a lot of room for growth. More importantly, its agile business model and brand authority should keep it at the forefront of the travel industry. And the network effect that fuels its business should reinforce its competitive edge, enhancing its inventory over time. That's why this growth stock is a smart buy.

2. Paycom Software

Paycom provides cloud-based human capital management (HCM) software to small and medium-sized businesses. Its platform is built around payroll, but it also includes tools for talent acquisition, time and labor management, and human resources functions like compliance and benefits administration.

More importantly, all of those applications are powered by a single database, eliminating the need to maintain employee data across multiple systems. That makes Paycom's platform less complex than the point solutions that many enterprises use to meet their HCM needs. Better yet, Paycom streamlines back-office workflow through self-service functionality and automation, allowing employees to manage certain tasks and transactions at their own convenience.

That value proposition continued to resonate with clients in the first quarter. Despite a tough macroeconomic environment, revenue jumped 30% to $353 million, operating margin expanded 100 basis points to 35.7%, and generally accepted accounting principles (GAAP) earnings soared 42% to $1.58 per diluted share. And investors have good reason to believe that momentum will continue.

Paycom estimates that it has captured just 5% of its addressable market, but the company is growing its sales presence and expanding its portfolio. Last year, Paycom launched the industry's first self-service payroll technology, and the product -- which is nicknamed Beti (Better Employee Transaction Interface) -- has already seen tremendous adoption. That type of innovation should keep Paycom on the leading edge of the HCM industry. That's why this growth stock is worth buying.