Shares of Old Dominion Freight Line (ODFL -7.35%) were falling today in sympathy with a disappointing report from rival Saia, another top less-than-truckload (LTL) carrier.

Combined with the report from ODFL the day before, Saia's update is clear evidence that the trade war and weakening economy is already having an effect on the trucking sector.

As of 11:58 a.m. ET, Old Dominion stock was down 6.7%, while Saia stock had plunged 29.1%.

Image source: Getty Images.

Trucking demand is weakening

Old Dominion managed to pass muster with its own first-quarter earnings report as results, though weak, lived up to analyst expectations.

ODFL said revenue fell 5.8% to $1.37 billion, which matched estimates, while earnings per share dropped 11% to $1.19, which was ahead of expectations at $1.14. Management said the results reflected the "ongoing softness in the domestic economy." Tonnage per day was down 6.3%, reflecting weakening demand in the industry.

Despite the weak results, management was able to reassure investors that it can weather the uncertainty in the economy.

Saia's earnings report seemed to shift investor perception of industry dynamics as it reported an increase in revenue in the first quarter, but a sharp drop in profit, showing it prioritized market share gains over profitability. Its revenue growth was also slower than in previous quarter, indicating that demand was weakening.

Saia's revenue rose 4.3% in the first quarter to $787.6 million, badly missing estimates at $811.5 million, while earnings per share tumbled from $3.38 to $1.86, well below expectations at $2.76.

The results from both companies clearly show softening pricing dynamics in an industry where capacity is key, and Saia noted that shipments failed to grow sequentially through the quarter as they typically do, which it blamed on an "uncertain macroeconomic environment."

What's next for ODFL and Saia

It's unclear what's happening next with tariffs or the trade war, but things seem likely to get worse before they get better for the LTL sector as Trump's "Liberation Day" announcement didn't even go into effect until April, when the first quarter was over.

These companies don't typically give guidance due to the volatility inherent in the business so investors should steel themselves for more challenges ahead. However, the LTL sector has historically been a winner, meaning over the long term these two stocks should be able to recover.