WASHINGTON — Since retiring two years ago, Joan Harris has upped her travel game.

Once or twice a year, she visits her two adult children in different states. She’s planning multiple other trips, including to a science fiction convention in Scotland and a Disney cruise soon after that, along with a trip next year to neolithic sites in Great Britain.

“I really have more money to spend now than when I was working,” said Harris, 64, an engineer who worked 29 years for the federal government and lives in Albuquerque, New Mexico.

Back then, she and her now-ex-husband were paying for their children’s college educations and piling money into savings accounts. Now, she’s splurging a bit and, for the first time, is willing to pay for first-class plane tickets. She plans to fly business class to Scotland and has arranged for a higher-level suite on the cruise.

“I suddenly realized, with my dad getting old and my mom dying, it’s like, ‘No, you can’t take it with you,’ ” she said. “I could become incapacitated to the point where I couldn’t enjoy something like going to Scotland or going on a cruise. So I better do it, right?”

Older Americans are fueling a sustained boost to the U.S. economy. Benefiting from outsize gains in the stock and housing markets over the past several years, they are accounting for a larger share of consumer spending — the principal driver of economic growth — than ever before.

And much of their spending is going toward higher-priced services like travel, health care and entertainment, putting further upward pressure on those prices — and on inflation. Such spending is relatively immune to the Federal Reserve’s push to slow growth and tame inflation through higher borrowing rates, because it rarely requires borrowing.

The so-called wealth effect, whereby rising home and stock values give people confidence to increase their spending, is a big reason why the economy has defied expectations of a sharp slowdown. Its unexpected strength, which is contributing to stickier inflation, has forced a shift in the Fed’s plans.

As recently as March, the Fed’s policymakers had projected that they would cut their benchmark rate three times this year. Since then, though, inflation measures have remained uncomfortably high, partly a consequence of brisk consumer spending. Chair Jerome Powell made clear recently that the Fed isn’t confident enough that inflation is sustainably easing to cut rates.

The Fed kept rates unchanged at 5.3% Wednesday.

Even as the Fed has jacked up borrowing costs, stock and home values have kept rising, enlarging the net worth of affluent households. Consider that household wealth grew by an average of 5.5% a year in the decade after the 2008-2009 Great Recession but that since 2018, it’s accelerated to nearly 9%.

Stock prices, as measured by the S&P 500 index, are about 72% higher than they were five years ago. Home values soared 58% from the end of 2018 through 2023, the Fed said.

All told, Americans’ wealth has ballooned from $98 trillion at the end of 2018 to $147 trillion five years later. Adjusting for inflation, the gains are less dramatic but still substantial.

But the gains are hardly universal. The wealthiest one-tenth of Americans own two-thirds of all household wealth. Still, wealth for the median household — the midpoint between the richest and poorest — rose 37% from 2019 to 2022, the sharpest rise on record since the 1980s, to $193,000.

Wealth is also disproportionately held by older Americans.

People age 55 and over now own nearly three-quarters of all household wealth, up from 68% in 2010.

In percentage terms since the pandemic, household net worth has also surged for younger households. But because younger adults started from a lower level, their gains haven’t been anywhere near enough to keep pace with older Americans.