The stock market has challenged investors over the past 18 months or so, but not so much that they should just sell and go away. Volatility is nothing new for the stock market, and it's something investors of all sorts have to grapple with regularly throughout their investing journey. 

Even in an uncertain economic environment where fears of a recession are still a common topic among investors, many wonderful businesses continue to deliver growth. Their stocks are poised for meaningful returns in the next bull market and beyond. 

Let's look at two such growth stocks investors shouldn't hesitate to buy in June and hold for the long term. 

1. Airbnb

Airbnb (ABNB -1.36%) isn't slowing down its growth trajectory as the travel industry roars back to life following the last few years of extreme volatility and stop-and-go recovery efforts related to the pandemic. Although the return of cross-border travel is certainly a factor that has aided in Airbnb's revitalized growth, it's actually a variety of catalysts driving the platform's success and enabling it to continue expanding its market share. 

Airbnb's platform benefits from both the supply and demand for short- and long-term rentals. Active listings were up 18% year over year in the first quarter. The gross booking value of stays reserved for the three-month period totaled more than $20 billion, up 22% year over year on a currency-neutral basis and 105% from four years ago.

Airbnb is already available in more than 220 countries and counting, but management said in the company's Q1 earnings report that it plans several additional launches starting in 2024. In the meantime, profits and cash flow are growing, people are continuing to live in Airbnb properties for longer periods (18% of stays are 28 days or longer), and almost half of all stays are a minimum of a week.  

Airbnb is tapping into the changing habits of travelers in a time when more people have the ability to blend work and travel because of remote and flex jobs. The company has also managed to maintain its asset-light model while entering a new segment of the accommodation market with its Airbnb-Friendly Apartments initiative. The program, which helps tenants locate apartments that they can live in but also host part-time on Airbnb, has seen landlord adoption increase at such a scale that it now includes 250 properties across the U.S., compared to 175 when the program launched last November.

Airbnb has plenty of room to run both within and outside of the vacation rental market, a reality that investors may want to capitalize on before the next bull market comes.  

2. Costco

Costco (COST -0.69%) is undeniably operating in a difficult environment, particularly in a time when big-box retailers struggle as inflation and fluctuating consumer spending drive already low-margin businesses downward. While Costco is not immune to these dynamics, it continues to report impressive sales and profits. Shares are up about 15% since the start of 2023, close to the S&P 500's performance in that same stretch of time. 

One of the core competitive advantages Costco continues to wield is its membership-based model. As of the most recent quarter, the company reported that its membership renewal rate in the U.S. and Canada was an impressive 92.6%, while its global renewal rate was north of 90%. At the end of the three-month period, Costco had 69.1 million household memberships, and 124.7 million cardholders in its membership base, a 7% increase on both counts on a year-over-year basis.

Its executive member base hit 31.3 million individuals in the quarter. That cohort of members now accounts for 73% of its global sales and more than 45% of its total paid members. A Costco executive membership costs $120 a year compared to the basic $60 membership and comes with a range of additional perks, like up to $1,000 in annual rewards from qualifying purchases.

One notable blight that affected big-box retailers recently and also accounted for declining margins is a rise in in-store theft, a trend that Costco largely avoided due to its membership model. With customers getting their member cards checked on the way in and receipts on the way out, it's simply much harder for thieves to get in and out undetected. Even as top and bottom line growth decelerates, it's worth pointing out that Costco still pulled in revenue of $235 billion and profits of $6 billion in the trailing 12 months alone. Most of those profits come from its membership fees.

This isn't a high-growth stock, but its sturdy business model can lend successive growth to the portfolios of investors who stay with the business for the long haul.