WASHINGTON Sept. 20 (AP)-- The U.S. trade deficit jumped to a record monthly high of $11.50 billion in July, reflecting a big drop in American exports such as aircraft and a big rise in imports of German luxury cars.

The Commerce Department said today that the deficit in goods and services increased by 1.9 percent from a revised June level of $11.28 billion. It marked the second straight month a new record has been set in the monthly series on goods and services, which the government began in 1992. The worsening deficit caught economists by surprise. They had been expecting a small improvement in the belief that slower growth in the United States would cut into the demand for imports.

Imports of goods and services did decline during the month, dropping 1.7 percent to $74.59 billion. But this drop was surpassed by a 2.3 percent decline in exports, which fell to $63.09 billion. The deficit is the difference between imports and exports.

"We continue to have a very large imbalance in trade," said Robert Dederick, economic consultant at Nothern Trust Co. in Chicago. "The fundamental reason is that we are a high spending country and a low savings country. That will not change overnight."

The wider-than-expected trade deficit put downward pressure on the dollar, with the U.S. currency declining slightly against both the Japanese yen and the German mark immediately after the trade report was released.

So far this year, the U.S. deficit in just goods is running at an annual rate of $188 billion, on track to be the worst showing in history.

The country's worsening trade problems represent a severe political problem for the Clinton administration, which has made trade a key priority of its foreign policy.

The administration has insisted the strategy is working, pointing to record high levels for U.S. exports, but critics note that imports are also at record highs, an increase they claim represents a transfer of American jobs overseas.

For July, America's deficit with Japan as usual represented the largest imbalance with any country, even though the $5.12 billion was 3.3 percent lower than the June deficit.

It marked the fourth straight month the deficit with Japan has declined. Today's report came as the Japanese government announced a new government stimulus package that U.S. officials praised as a constructive effort to boost Japanese demand for American exports.

The deficit with China shot up 11 percent to $3.33 billion, as America imported more goods from China than ever before.

The deficit with Germany also set a record at $1.9 billion as exports of Germany luxury cars and auto parts climbed by $300 million.

Analysts had forecast this increase, believing that Germany would be the principal beneficiary of a summer trade fight with Japan in which the United States had threatened to knock Japanese luxury cars out of the American market. Before the dispute was settled at the 11th hour, Japan had curtailed shipments of many of the targeted autos rather than risk punitive tariffs of 100 percent.

With all of Western Europe, the United States recorded a deficit of $3.1 billion, the highest since July 1987. Analysts said weak economic growth in this region had cut into U.S. exports.

America's trade deficit with Mexico totaled $1.28 billion in July, down 14 percent from the June level. However, the United States is on track to record a record $15 billion deficit with Mexico this year. This sharp turnaround from a surplus last year reflects the severe consequences of Mexico's currency crisis, which has reduced the ability of Mexicans to buy American products.

U.S. exports of goods dropped by $1.32 billion in July. Half of that decline reflected a $685 million plunge in sales of commercial aircraft. So far this year, sales of jetliners, America's leading manufactured export, are down $3.11 billion from the same period a year ago.

The government noted that U.S. exports of telecommunications equipment at $1.7 billion and computer accessories at $2.4 billion were the highest on record.

Imports of goods dropped by $1.23 billion, even though demand by American businesses for capital goods established a record high for a fifth straight month, climbing to $18.9 billion. This category reflects the strong investment spending boom in the United States.

Part of the decline in imports reflected an 8.9 percent decrease in crude oil, which fell by $354 million to $3.63 billion.