The stock market opened the new week on a generally positive note, with market participants looking primarily at favorable indications from trade negotiations between the U.S. and China in hopes of greater macroeconomic stability in the year to come. As of 11 a.m. EST on Monday, the Dow Jones Industrial Average (DJINDICES:^DJI) had climbed 33 points to 28,857. The S&P 500 (SNPINDEX:^GSPC) gained 9 points to 3,274, and the Nasdaq Composite (NASDAQINDEX:^IXIC) picked up 30 points to 9,209.

The holiday shopping season always offers a valuable look at the health of the consumer economy, and high-end yoga apparel specialist lululemon athletica (NASDAQ:LULU) gave some signs that consumers are stronger than ever. Airline investors hope that they'll see the same optimism when Delta Air Lines (NYSE:DAL) reports its latest results on Tuesday.

Holiday cheer for Lululemon

Shares of Lululemon rose 3% after it gave its latest reading on how the holiday season went. Based on the boosts to guidance that the company made, the end of 2019 went well.

A lululemon store on a street next to a dome-shaped building.

Image source: Lululemon.

On the sales front, Lululemon said that it now expects fourth-quarter revenue between $1.37 billion and $1.38 billion. That's up by roughly $50 million to $55 million from its previous guidance. The retailer sees comparable-store sales having climbed by percentages in the mid to high teens year over year, versus earlier projections for low-double-digit percentage increases in comps.

Earnings also look more promising. The yoga specialist said it now believes quarterly earnings will be between $2.22 and $2.25 per share, up from its previous projections for $2.10 to $2.13.

Investors were pleased with the enthusiasm of CEO Calvin McDonald, who said, "We're excited by the momentum in our business over the holiday period with guests responding well to our innovative merchandise offerings." Shareholders are also feeling that optimism, and Lululemon is therefore continuing its impressive run higher.

Delta: Cleared for takeoff?

Meanwhile, shares of Delta Air Lines were higher by a fraction of a percentage point. Investors didn't have any huge news today, although a decline in oil prices gave a bit of a lift to the airline industry more broadly.

Some investors have been nervous about airline stocks recently. After the category's solid performance in recent years, naysayers believe that a cyclical downturn in the broader economy could force the growth story for airlines to take a pause and even lead to a broader recession. To the extent that such a move might lead to lower earnings, it could push share prices for Delta and its peers downward.

Yet coming into its quarterly report, Delta has been optimistic about its prospects. Even though the airline expects to have to increase compensation and boost personnel counts in order to bolster its growth prospects, greater fuel efficiency from newer aircraft in its fleet should help to counteract some of the cost increases elsewhere. Moreover, between strong demand for passenger travel and its lucrative partnership with branded credit card provider American Express, Delta thinks that 2020 looks encouraging.

The airline's quarterly report will go a long way toward showing whether bulls or bears on the industry are correct about economic conditions right now. With the stock trading at a single-digit P/E, though, the odds appear to be on Delta's side.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.