Delta Air Lines on Monday slashed its first-quarter profit estimates by half, sending its shares down 14%, and its CEO said the environment had weakened due to U.S. economic uncertainty.

Delta Air Lines Inc. cut its profit expectations for the first quarter roughly by half on weakening travel demand, the latest sign that economic worries are pressuring consumer spending.

City Council president JP Morrell expressed his "dismay and extreme concern" Monday about Mayor LaToya Cantrell's trip to attend a conference in Washington, D.C. Why it matters: The trip is the first test of the council's ordinance that temporarily bans non-essential travel for city employees.

While in Washington, Cantrell will participate in community engagement efforts to support a program for future youth leaders.

More than half a million people are facing travel disruption at German airports on Monday where a 24-hour strike has led to thousands of flight cancellations in a dispute about workers' pay. Fiona Jones reports.

Strikes began at major German airports at midnight on Sunday (23:00 GMT), with public service workers, ground staff and aviation security called out for 24 hours by the verdi trade union in two different wage disputes.